Prototype(s) d’une commande#

  • Une commande réalise une tâche (trier, sélectionner, ouvrir, aligner des reads,…).

  • Elle dispose d’un certain nombre d’arguments qui peuvent être facultatifs et qui peuvent modifier son mode de fonctionnement.

    • Les noms des arguments ne sont pas standardisés

  • Ces arguments peuvent ou non prendre des valeurs.

  • De manière générale une instruction dans le terminal commence toujours par le nom d’une commande

  • Dans le premier exemple ci-dessous on dira ‘moins v’.

# Exemple d'argument sans valeur associée
# v pouvant signifier verbose, version (ou autre suivant la commande).
module load fastqc
fastqc -v # quelle est la version du logiciel fastqc sur ce serveur ?
FastQC v0.11.9
?2004h

# Exemple de commande avec une valeur choisie par l'utilisateur
cd /shared/projects/2325_ebaii/
# Exemple d'argument avec valeur associée 
tree -L 1 # Afficher sous forme d’arbre l’arborescence sur un niveaux
.
├── atelier_variant
├── coursLinux
├── SingleCell
├── TP_croisement
└── tp_worflow

5 directories, 0 files
  • De manière générale, Ies arguments peuvent être utilisés sous leurs formes courtes ou sous leurs formes longues (plus explicites/lisibles mais plus longues à taper…).

  • Les formes longues sont généralement précédées de deux tirets (dans l’exemple ci dessous on dira ‘moins-moins help)

# Demander de l'aide (help) sur fastqc avec l'argument -h
fastqc -h  
            FastQC - A high throughput sequence QC analysis tool

SYNOPSIS

	fastqc seqfile1 seqfile2 .. seqfileN

    fastqc [-o output dir] [--(no)extract] [-f fastq|bam|sam] 
           [-c contaminant file] seqfile1 .. seqfileN

DESCRIPTION

    FastQC reads a set of sequence files and produces from each one a quality
    control report consisting of a number of different modules, each one of 
    which will help to identify a different potential type of problem in your
    data.
    
    If no files to process are specified on the command line then the program
    will start as an interactive graphical application.  If files are provided
    on the command line then the program will run with no user interaction
    required.  In this mode it is suitable for inclusion into a standardised
    analysis pipeline.
    
    The options for the program as as follows:
    
    -h --help       Print this help file and exit
    
    -v --version    Print the version of the program and exit
    
    -o --outdir     Create all output files in the specified output directory.
                    Please note that this directory must exist as the program
                    will not create it.  If this option is not set then the 
                    output file for each sequence file is created in the same
                    directory as the sequence file which was processed.
                    
    --casava        Files come from raw casava output. Files in the same sample
                    group (differing only by the group number) will be analysed
                    as a set rather than individually. Sequences with the filter
                    flag set in the header will be excluded from the analysis.
                    Files must have the same names given to them by casava
                    (including being gzipped and ending with .gz) otherwise they
                    won't be grouped together correctly.
                    
    --nano          Files come from nanopore sequences and are in fast5 format. In
                    this mode you can pass in directories to process and the program
                    will take in all fast5 files within those directories and produce
                    a single output file from the sequences found in all files.                    
                    
    --nofilter      If running with --casava then don't remove read flagged by
                    casava as poor quality when performing the QC analysis.
                   
    --extract       If set then the zipped output file will be uncompressed in
                    the same directory after it has been created.  By default
                    this option will be set if fastqc is run in non-interactive
                    mode.
                    
    -j --java       Provides the full path to the java binary you want to use to
                    launch fastqc. If not supplied then java is assumed to be in
                    your path.
                   
    --noextract     Do not uncompress the output file after creating it.  You
                    should set this option if you do not wish to uncompress
                    the output when running in non-interactive mode.
                    
    --nogroup       Disable grouping of bases for reads >50bp. All reports will
                    show data for every base in the read.  WARNING: Using this
                    option will cause fastqc to crash and burn if you use it on
                    really long reads, and your plots may end up a ridiculous size.
                    You have been warned!
                    
    --min_length    Sets an artificial lower limit on the length of the sequence
                    to be shown in the report.  As long as you set this to a value
                    greater or equal to your longest read length then this will be
                    the sequence length used to create your read groups.  This can
                    be useful for making directly comaparable statistics from 
                    datasets with somewhat variable read lengths.
                    
    -f --format     Bypasses the normal sequence file format detection and
                    forces the program to use the specified format.  Valid
                    formats are bam,sam,bam_mapped,sam_mapped and fastq
                    
    -t --threads    Specifies the number of files which can be processed
                    simultaneously.  Each thread will be allocated 250MB of
                    memory so you shouldn't run more threads than your
                    available memory will cope with, and not more than
                    6 threads on a 32 bit machine
                  
    -c              Specifies a non-default file which contains the list of
    --contaminants  contaminants to screen overrepresented sequences against.
                    The file must contain sets of named contaminants in the
                    form name[tab]sequence.  Lines prefixed with a hash will
                    be ignored.

    -a              Specifies a non-default file which contains the list of
    --adapters      adapter sequences which will be explicity searched against
                    the library. The file must contain sets of named adapters
                    in the form name[tab]sequence.  Lines prefixed with a hash
                    will be ignored.
                    
    -l              Specifies a non-default file which contains a set of criteria
    --limits        which will be used to determine the warn/error limits for the
                    various modules.  This file can also be used to selectively 
                    remove some modules from the output all together.  The format
                    needs to mirror the default limits.txt file found in the
                    Configuration folder.
                    
   -k --kmers       Specifies the length of Kmer to look for in the Kmer content
                    module. Specified Kmer length must be between 2 and 10. Default
                    length is 7 if not specified.
                    
   -q --quiet       Supress all progress messages on stdout and only report errors.
   
   -d --dir         Selects a directory to be used for temporary files written when
                    generating report images. Defaults to system temp directory if
                    not specified.
                    
BUGS

    Any bugs in fastqc should be reported either to simon.andrews@babraham.ac.uk
    or in www.bioinformatics.babraham.ac.uk/bugzilla/
                   
    
# La commande précédente est équivalente mais un peu plus lisible
fastqc --help
            FastQC - A high throughput sequence QC analysis tool

SYNOPSIS

	fastqc seqfile1 seqfile2 .. seqfileN

    fastqc [-o output dir] [--(no)extract] [-f fastq|bam|sam] 
           [-c contaminant file] seqfile1 .. seqfileN

DESCRIPTION

    FastQC reads a set of sequence files and produces from each one a quality
    control report consisting of a number of different modules, each one of 
    which will help to identify a different potential type of problem in your
    data.
    
    If no files to process are specified on the command line then the program
    will start as an interactive graphical application.  If files are provided
    on the command line then the program will run with no user interaction
    required.  In this mode it is suitable for inclusion into a standardised
    analysis pipeline.
    
    The options for the program as as follows:
    
    -h --help       Print this help file and exit
    
    -v --version    Print the version of the program and exit
    
    -o --outdir     Create all output files in the specified output directory.
                    Please note that this directory must exist as the program
                    will not create it.  If this option is not set then the 
                    output file for each sequence file is created in the same
                    directory as the sequence file which was processed.
                    
    --casava        Files come from raw casava output. Files in the same sample
                    group (differing only by the group number) will be analysed
                    as a set rather than individually. Sequences with the filter
                    flag set in the header will be excluded from the analysis.
                    Files must have the same names given to them by casava
                    (including being gzipped and ending with .gz) otherwise they
                    won't be grouped together correctly.
                    
    --nano          Files come from nanopore sequences and are in fast5 format. In
                    this mode you can pass in directories to process and the program
                    will take in all fast5 files within those directories and produce
                    a single output file from the sequences found in all files.                    
                    
    --nofilter      If running with --casava then don't remove read flagged by
                    casava as poor quality when performing the QC analysis.
                   
    --extract       If set then the zipped output file will be uncompressed in
                    the same directory after it has been created.  By default
                    this option will be set if fastqc is run in non-interactive
                    mode.
                    
    -j --java       Provides the full path to the java binary you want to use to
                    launch fastqc. If not supplied then java is assumed to be in
                    your path.
                   
    --noextract     Do not uncompress the output file after creating it.  You
                    should set this option if you do not wish to uncompress
                    the output when running in non-interactive mode.
                    
    --nogroup       Disable grouping of bases for reads >50bp. All reports will
                    show data for every base in the read.  WARNING: Using this
                    option will cause fastqc to crash and burn if you use it on
                    really long reads, and your plots may end up a ridiculous size.
                    You have been warned!
                    
    --min_length    Sets an artificial lower limit on the length of the sequence
                    to be shown in the report.  As long as you set this to a value
                    greater or equal to your longest read length then this will be
                    the sequence length used to create your read groups.  This can
                    be useful for making directly comaparable statistics from 
                    datasets with somewhat variable read lengths.
                    
    -f --format     Bypasses the normal sequence file format detection and
                    forces the program to use the specified format.  Valid
                    formats are bam,sam,bam_mapped,sam_mapped and fastq
                    
    -t --threads    Specifies the number of files which can be processed
                    simultaneously.  Each thread will be allocated 250MB of
                    memory so you shouldn't run more threads than your
                    available memory will cope with, and not more than
                    6 threads on a 32 bit machine
                  
    -c              Specifies a non-default file which contains the list of
    --contaminants  contaminants to screen overrepresented sequences against.
                    The file must contain sets of named contaminants in the
                    form name[tab]sequence.  Lines prefixed with a hash will
                    be ignored.

    -a              Specifies a non-default file which contains the list of
    --adapters      adapter sequences which will be explicity searched against
                    the library. The file must contain sets of named adapters
                    in the form name[tab]sequence.  Lines prefixed with a hash
                    will be ignored.
                    
    -l              Specifies a non-default file which contains a set of criteria
    --limits        which will be used to determine the warn/error limits for the
                    various modules.  This file can also be used to selectively 
                    remove some modules from the output all together.  The format
                    needs to mirror the default limits.txt file found in the
                    Configuration folder.
                    
   -k --kmers       Specifies the length of Kmer to look for in the Kmer content
                    module. Specified Kmer length must be between 2 and 10. Default
                    length is 7 if not specified.
                    
   -q --quiet       Supress all progress messages on stdout and only report errors.
   
   -d --dir         Selects a directory to be used for temporary files written when
                    generating report images. Defaults to system temp directory if
                    not specified.
                    
BUGS

    Any bugs in fastqc should be reported either to simon.andrews@babraham.ac.uk
    or in www.bioinformatics.babraham.ac.uk/bugzilla/
                   
    

Trouver de l’aide !#

Appeler la police, appeler son collègue, chercher sur internet ou utiliser la commande man (manuel)

# obtenir de l'aide sur la commande ls
man ls  
LS(1)                            User Commands                           LS(1)



NAME
       ls - list directory contents

SYNOPSIS
       ls [OPTION]... [FILE]...

DESCRIPTION
       List  information  about  the FILEs (the current directory by default).
       Sort entries alphabetically if none of -cftuvSUX nor --sort  is  speci‐
       fied.

       Mandatory  arguments  to  long  options are mandatory for short options
       too.

       -a, --all
              do not ignore entries starting with .

       -A, --almost-all
              do not list implied . and ..

       --author
              with -l, print the author of each file

       -b, --escape
              print C-style escapes for nongraphic characters

       --block-size=SIZE
              scale sizes by SIZE before printing them; e.g., '--block-size=M'
              prints sizes in units of 1,048,576 bytes; see SIZE format below

       -B, --ignore-backups
              do not list implied entries ending with ~

       -c     with -lt: sort by, and show, ctime (time of last modification of
              file status information); with -l: show ctime and sort by  name;
              otherwise: sort by ctime, newest first

       -C     list entries by columns

       --color[=WHEN]
              colorize  the  output;  WHEN can be 'never', 'auto', or 'always'
              (the default); more info below

       -d, --directory
              list directories themselves, not their contents

       -D, --dired
              generate output designed for Emacs' dired mode

       -f     do not sort, enable -aU, disable -ls --color

       -F, --classify
              append indicator (one of */=>@|) to entries

       --file-type
              likewise, except do not append '*'

       --format=WORD
              across -x, commas -m, horizontal -x, long -l, single-column  -1,
              verbose -l, vertical -C

       --full-time
              like -l --time-style=full-iso

       -g     like -l, but do not list owner

       --group-directories-first
              group directories before files;

              can   be  augmented  with  a  --sort  option,  but  any  use  of
              --sort=none (-U) disables grouping

       -G, --no-group
              in a long listing, don't print group names

       -h, --human-readable
              with -l, print sizes in human readable format (e.g., 1K 234M 2G)

       --si   likewise, but use powers of 1000 not 1024

       -H, --dereference-command-line
              follow symbolic links listed on the command line

       --dereference-command-line-symlink-to-dir
              follow each command line symbolic link

              that points to a directory

       --hide=PATTERN
              do not list implied entries matching shell  PATTERN  (overridden
              by -a or -A)

       --indicator-style=WORD
              append indicator with style WORD to entry names: none (default),
              slash (-p), file-type (--file-type), classify (-F)

       -i, --inode
              print the index number of each file

       -I, --ignore=PATTERN
              do not list implied entries matching shell PATTERN

       -k, --kibibytes
              default to 1024-byte blocks for disk usage

       -l     use a long listing format

       -L, --dereference
              when showing file information for a symbolic link, show informa‐
              tion  for  the file the link references rather than for the link
              itself

       -m     fill width with a comma separated list of entries

       -n, --numeric-uid-gid
              like -l, but list numeric user and group IDs

       -N, --literal
              print raw entry names (don't treat e.g. control characters  spe‐
              cially)

       -o     like -l, but do not list group information

       -p, --indicator-style=slash
              append / indicator to directories

       -q, --hide-control-chars
              print ? instead of nongraphic characters

       --show-control-chars
              show nongraphic characters as-is (the default, unless program is
              'ls' and output is a terminal)

       -Q, --quote-name
              enclose entry names in double quotes

       --quoting-style=WORD
              use quoting style WORD for entry names: literal, locale,  shell,
              shell-always, c, escape

       -r, --reverse
              reverse order while sorting

       -R, --recursive
              list subdirectories recursively

       -s, --size
              print the allocated size of each file, in blocks

       -S     sort by file size

       --sort=WORD
              sort  by  WORD instead of name: none (-U), size (-S), time (-t),
              version (-v), extension (-X)

       --time=WORD
              with -l, show time as WORD instead of default modification time:
              atime or access or use (-u) ctime or status (-c); also use spec‐
              ified time as sort key if --sort=time

       --time-style=STYLE
              with -l, show times using style STYLE: full-iso, long-iso,  iso,
              locale,  or  +FORMAT;  FORMAT  is interpreted like in 'date'; if
              FORMAT  is  FORMAT1<newline>FORMAT2,  then  FORMAT1  applies  to
              non-recent  files  and FORMAT2 to recent files; if STYLE is pre‐
              fixed with 'posix-', STYLE takes effect only outside  the  POSIX
              locale

       -t     sort by modification time, newest first

       -T, --tabsize=COLS
              assume tab stops at each COLS instead of 8

       -u     with  -lt:  sort by, and show, access time; with -l: show access
              time and sort by name; otherwise: sort by access time

       -U     do not sort; list entries in directory order

       -v     natural sort of (version) numbers within text

       -w, --width=COLS
              assume screen width instead of current value

       -x     list entries by lines instead of by columns

       -X     sort alphabetically by entry extension

       -1     list one file per line

       SELinux options:

       --lcontext
              Display security context.   Enable -l. Lines  will  probably  be
              too wide for most displays.

       -Z, --context
              Display  security context so it fits on most displays.  Displays
              only mode, user, group, security context and file name.

       --scontext
              Display only security context and file name.

       --help display this help and exit

       --version
              output version information and exit

       SIZE is an integer and optional unit (example:  10M  is  10*1024*1024).
       Units  are K, M, G, T, P, E, Z, Y (powers of 1024) or KB, MB, ... (pow‐
       ers of 1000).

       Using color to distinguish file types is disabled both by  default  and
       with  --color=never.  With --color=auto, ls emits color codes only when
       standard output is connected to a terminal.  The LS_COLORS  environment
       variable can change the settings.  Use the dircolors command to set it.

   Exit status:
       0      if OK,

       1      if minor problems (e.g., cannot access subdirectory),

       2      if serious trouble (e.g., cannot access command-line argument).

       GNU  coreutils  online  help:  <http://www.gnu.org/software/coreutils/>
       Report ls translation bugs to <http://translationproject.org/team/>

AUTHOR
       Written by Richard M. Stallman and David MacKenzie.

COPYRIGHT
       Copyright © 2013 Free Software Foundation, Inc.   License  GPLv3+:  GNU
       GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
       This  is  free  software:  you  are free to change and redistribute it.
       There is NO WARRANTY, to the extent permitted by law.

SEE ALSO
       The full documentation for ls is maintained as a  Texinfo  manual.   If
       the  info and ls programs are properly installed at your site, the com‐
       mand

              info coreutils 'ls invocation'

       should give you access to the complete manual.



GNU coreutils 8.22                April 2018                             LS(1)
# obtenir de l'aide sur la commande man ...
man man  
MAN(1)                        Manual pager utils                        MAN(1)



NAME
       man - an interface to the on-line reference manuals

SYNOPSIS
       man  [-C  file]  [-d]  [-D]  [--warnings[=warnings]]  [-R encoding] [-L
       locale] [-m system[,...]] [-M path] [-S list]  [-e  extension]  [-i|-I]
       [--regex|--wildcard]   [--names-only]  [-a]  [-u]  [--no-subpages]  [-P
       pager] [-r prompt] [-7] [-E encoding] [--no-hyphenation] [--no-justifi‐
       cation]  [-p  string]  [-t]  [-T[device]]  [-H[browser]] [-X[dpi]] [-Z]
       [[section] page ...] ...
       man -k [apropos options] regexp ...
       man -K [-w|-W] [-S list] [-i|-I] [--regex] [section] term ...
       man -f [whatis options] page ...
       man -l [-C file] [-d] [-D] [--warnings[=warnings]]  [-R  encoding]  [-L
       locale]  [-P  pager]  [-r  prompt]  [-7] [-E encoding] [-p string] [-t]
       [-T[device]] [-H[browser]] [-X[dpi]] [-Z] file ...
       man -w|-W [-C file] [-d] [-D] page ...
       man -c [-C file] [-d] [-D] page ...
       man [-?V]

DESCRIPTION
       man is the system's manual pager. Each page argument given  to  man  is
       normally  the  name of a program, utility or function.  The manual page
       associated with each of these arguments is then found and displayed.  A
       section,  if  provided, will direct man to look only in that section of
       the manual.  The default action is to search in all  of  the  available
       sections, following a pre-defined order and to show only the first page
       found, even if page exists in several sections.

       The table below shows the section numbers of the manual followed by the
       types of pages they contain.


       1   Executable programs or shell commands
       2   System calls (functions provided by the kernel)
       3   Library calls (functions within program libraries)
       4   Special files (usually found in /dev)
       5   File formats and conventions eg /etc/passwd
       6   Games
       7   Miscellaneous  (including  macro  packages  and  conventions), e.g.
           man(7), groff(7)
       8   System administration commands (usually only for root)
       9   Kernel routines [Non standard]

       A manual page consists of several sections.

       Conventional  section  names  include  NAME,  SYNOPSIS,  CONFIGURATION,
       DESCRIPTION,  OPTIONS,  EXIT STATUS, RETURN VALUE, ERRORS, ENVIRONMENT,
       FILES, VERSIONS, CONFORMING TO,  NOTES,  BUGS,  EXAMPLE,  AUTHORS,  and
       SEE ALSO.

       The following conventions apply to the SYNOPSIS section and can be used
       as a guide in other sections.


       bold text          type exactly as shown.
       italic text        replace with appropriate argument.
       [-abc]             any or all arguments within [ ] are optional.
       -a|-b              options delimited by | cannot be used together.
       argument ...       argument is repeatable.
       [expression] ...   entire expression within [ ] is repeatable.

       Exact rendering may vary depending on the output device.  For instance,
       man will usually not be able to render italics when running in a termi‐
       nal, and will typically use underlined or coloured text instead.

       The command or function illustration is a pattern that should match all
       possible invocations.  In some cases it is advisable to illustrate sev‐
       eral exclusive invocations as is shown in the SYNOPSIS section of  this
       manual page.

EXAMPLES
       man ls
           Display the manual page for the item (program) ls.

       man -a intro
           Display,  in  succession,  all  of the available intro manual pages
           contained within the manual.  It is possible to quit  between  suc‐
           cessive displays or skip any of them.

       man -t alias | lpr -Pps
           Format  the manual page referenced by `alias', usually a shell man‐
           ual page, into the default troff or groff format and pipe it to the
           printer  named  ps.   The default output for groff is usually Post‐
           Script.  man --help should advise as to which processor is bound to
           the -t option.

       man -l -Tdvi ./foo.1x.gz > ./foo.1x.dvi
           This  command  will  decompress  and format the nroff source manual
           page ./foo.1x.gz into a device independent (dvi) file.   The  redi‐
           rection is necessary as the -T flag causes output to be directed to
           stdout with no pager.  The output could be viewed  with  a  program
           such  as  xdvi or further processed into PostScript using a program
           such as dvips.

       man -k printf
           Search the short descriptions and manual page names for the keyword
           printf  as  regular expression.  Print out any matches.  Equivalent
           to apropos -r printf.

       man -f smail
           Lookup the manual pages referenced by smail and print out the short
           descriptions of any found.  Equivalent to whatis -r smail.

OVERVIEW
       Many  options are available to man in order to give as much flexibility
       as possible to the user.  Changes can be made to the search path,  sec‐
       tion  order,  output  processor,  and  other  behaviours and operations
       detailed below.

       If set, various environment variables are interrogated to determine the
       operation  of  man.   It  is  possible  to set the `catch all' variable
       $MANOPT to any string in command line format with  the  exception  that
       any  spaces  used as part of an option's argument must be escaped (pre‐
       ceded by a backslash).  man will parse $MANOPT prior to parsing its own
       command  line.   Those options requiring an argument will be overridden
       by the same options found on the command line.  To  reset  all  of  the
       options set in $MANOPT, -D can be specified as the initial command line
       option.  This will allow man to `forget' about the options specified in
       $MANOPT although they must still have been valid.

       The  manual  pager  utilities  packaged as man-db make extensive use of
       index database caches.  These caches contain information such as  where
       each  manual  page  can  be found on the filesystem and what its whatis
       (short one line description of the man page) contains, and allow man to
       run  faster  than  if it had to search the filesystem each time to find
       the appropriate manual page.  If requested using  the  -u  option,  man
       will  ensure  that  the caches remain consistent, which can obviate the
       need to manually run software to update traditional whatis  text  data‐
       bases.

       If  man  cannot  find a mandb initiated index database for a particular
       manual page hierarchy, it will still search for  the  requested  manual
       pages,  although  file globbing will be necessary to search within that
       hierarchy.  If whatis or apropos fails to find an index it will try  to
       extract information from a traditional whatis database instead.

       These  utilities  support  compressed  source  nroff  files  having, by
       default, the extensions of .Z, .z and .gz.  It is possible to deal with
       any  compression  extension, but this information must be known at com‐
       pile time.  Also, by default, any cat  pages  produced  are  compressed
       using gzip.  Each `global' manual page hierarchy such as /usr/share/man
       or /usr/X11R6/man may have any directory as  its  cat  page  hierarchy.
       Traditionally  the cat pages are stored under the same hierarchy as the
       man pages, but for reasons such as those specified in the File  Hierar‐
       chy  Standard  (FHS),  it  may  be better to store them elsewhere.  For
       details on how to do this, please read manpath(5).  For details on  why
       to do this, read the standard.

       International  support is available with this package.  Native language
       manual pages are accessible (if available on your system)  via  use  of
       locale  functions.   To  activate  such support, it is necessary to set
       either $LC_MESSAGES, $LANG  or  another  system  dependent  environment
       variable to your language locale, usually specified in the POSIX 1003.1
       based format:

       <language>[_<territory>[.<character-set>[,<version>]]]

       If the desired page is available in your locale, it will  be  displayed
       in lieu of the standard (usually American English) page.

       Support  for  international message catalogues is also featured in this
       package and can be activated in the same way, again if  available.   If
       you  find  that  the  manual pages and message catalogues supplied with
       this package are not available in your native language  and  you  would
       like  to supply them, please contact the maintainer who will be coordi‐
       nating such activity.

       For information regarding other features and extensions available  with
       this manual pager, please read the documents supplied with the package.

DEFAULTS
       man  will search for the desired manual pages within the index database
       caches. If the -u option is given, a cache consistency  check  is  per‐
       formed  to  ensure the databases accurately reflect the filesystem.  If
       this option is always given, it is not generally necessary to run mandb
       after the caches are initially created, unless a cache becomes corrupt.
       However, the cache consistency check can be slow on systems  with  many
       manual  pages  installed, so it is not performed by default, and system
       administrators may wish to run mandb every week or so to keep the data‐
       base  caches  fresh.   To forestall problems caused by outdated caches,
       man will fall back to file globbing if a cache lookup fails, just as it
       would if no cache was present.

       Once  a  manual page has been located, a check is performed to find out
       if a relative preformatted `cat' file already exists and is newer  than
       the nroff file.  If it does and is, this preformatted file is (usually)
       decompressed and then displayed, via use of a pager.  The pager can  be
       specified  in  a number of ways, or else will fall back to a default is
       used (see option -P for details).  If no cat is found or is older  than
       the  nroff  file, the nroff is filtered through various programs and is
       shown immediately.

       If a cat file can be produced (a relative cat directory exists and  has
       appropriate  permissions),  man will compress and store the cat file in
       the background.

       The filters are deciphered by a number of means. Firstly,  the  command
       line option -p or the environment variable $MANROFFSEQ is interrogated.
       If -p was not used and the environment variable was not set,  the  ini‐
       tial  line  of  the nroff file is parsed for a preprocessor string.  To
       contain a valid preprocessor string, the first line must resemble

       '\" <string>

       where string can be any combination of letters described by  option  -p
       below.

       If  none of the above methods provide any filter information, a default
       set is used.

       A formatting pipeline is formed from the filters and the  primary  for‐
       matter  (nroff or [tg]roff with -t) and executed.  Alternatively, if an
       executable program mandb_nfmt (or mandb_tfmt with -t) exists in the man
       tree  root,  it  is executed instead.  It gets passed the manual source
       file, the preprocessor string, and optionally the device specified with
       -T or -E as arguments.

OPTIONS
       Non argument options that are duplicated either on the command line, in
       $MANOPT, or both, are not harmful.  For options that require  an  argu‐
       ment, each duplication will override the previous argument value.

   General options
       -C file, --config-file=file
              Use  this  user  configuration  file  rather than the default of
              ~/.manpath.

       -d, --debug
              Print debugging information.

       -D, --default
              This option is normally issued as  the  very  first  option  and
              resets  man's  behaviour  to  its  default.  Its use is to reset
              those options that may have been set in  $MANOPT.   Any  options
              that follow -D will have their usual effect.

       --warnings[=warnings]
              Enable  warnings from groff.  This may be used to perform sanity
              checks on the source text of manual pages.  warnings is a comma-
              separated  list  of  warning  names;  if it is not supplied, the
              default is "mac".  See the “Warnings” node in info groff  for  a
              list of available warning names.

   Main modes of operation
       -f, --whatis
              Equivalent to whatis.  Display a short description from the man‐
              ual page, if available. See whatis(1) for details.

       -k, --apropos
              Equivalent to apropos.  Search the short  manual  page  descrip‐
              tions  for keywords and display any matches.  See apropos(1) for
              details.

       -K, --global-apropos
              Search for text in all manual  pages.   This  is  a  brute-force
              search,  and is likely to take some time; if you can, you should
              specify a section to reduce the number of pages that need to  be
              searched.   Search terms may be simple strings (the default), or
              regular expressions if the --regex option is used.

       -l, --local-file
              Activate `local' mode.  Format and display  local  manual  files
              instead  of  searching  through  the system's manual collection.
              Each manual page argument will be interpreted as an nroff source
              file in the correct format.  No cat file is produced.  If '-' is
              listed as one of the arguments, input will be taken from  stdin.
              When  this  option  is  not used, and man fails to find the page
              required, before displaying the error message,  it  attempts  to
              act as if this option was supplied, using the name as a filename
              and looking for an exact match.

       -w, --where, --path, --location
              Don't actually display the manual pages, but do print the  loca‐
              tion(s) of the source nroff files that would be formatted.

       -W, --where-cat, --location-cat
              Don't  actually display the manual pages, but do print the loca‐
              tion(s) of the cat files that would be displayed.  If -w and  -W
              are both specified, print both separated by a space.

       -c, --catman
              This  option  is  not for general use and should only be used by
              the catman program.

       -R encoding, --recode=encoding
              Instead of formatting the manual page in the usual  way,  output
              its  source converted to the specified encoding.  If you already
              know the encoding of the source file,  you  can  also  use  man‐
              conv(1)  directly.   However,  this option allows you to convert
              several manual pages to a  single  encoding  without  having  to
              explicitly  state  the encoding of each, provided that they were
              already installed in a structure similar to a manual page  hier‐
              archy.

   Finding manual pages
       -L locale, --locale=locale
              man will normally determine your current locale by a call to the
              C function setlocale(3) which interrogates  various  environment
              variables, possibly including $LC_MESSAGES and $LANG.  To tempo‐
              rarily override the determined value, use this option to  supply
              a  locale  string  directly  to man.  Note that it will not take
              effect until the search for pages actually begins.  Output  such
              as  the  help  message will always be displayed in the initially
              determined locale.

       -m system[,...], --systems=system[,...]
              If this system has access to  other  operating  system's  manual
              pages,  they can be accessed using this option.  To search for a
              manual page from NewOS's manual page collection, use the  option
              -m NewOS.

              The  system  specified  can  be a combination of comma delimited
              operating system names.  To include a search of the native oper‐
              ating  system's manual pages, include the system name man in the
              argument string.  This option will override the $SYSTEM environ‐
              ment variable.

       -M path, --manpath=path
              Specify  an alternate manpath to use.  By default, man uses man‐
              path derived code to determine the path to search.  This  option
              overrides the $MANPATH environment variable and causes option -m
              to be ignored.

              A path specified as a manpath must be the root of a manual  page
              hierarchy  structured  into  sections as described in the man-db
              manual (under "The manual page system").  To view  manual  pages
              outside such hierarchies, see the -l option.

       -S list, -s list, --sections=list
              List  is  a  colon-  or comma-separated list of `order specific'
              manual sections to search.  This option overrides  the  $MANSECT
              environment  variable.   (The  -s  spelling is for compatibility
              with System V.)

       -e sub-extension, --extension=sub-extension
              Some systems incorporate large packages of manual pages, such as
              those  that accompany the Tcl package, into the main manual page
              hierarchy.  To get around the problem of having two manual pages
              with  the  same name such as exit(3), the Tcl pages were usually
              all assigned to section l.  As this is unfortunate,  it  is  now
              possible  to put the pages in the correct section, and to assign
              a specific `extension' to them, in this case, exit(3tcl).  Under
              normal  operation,  man  will  display  exit(3) in preference to
              exit(3tcl).  To negotiate this situation and to avoid having  to
              know  which  section  the page you require resides in, it is now
              possible to give man a  sub-extension  string  indicating  which
              package  the page must belong to.  Using the above example, sup‐
              plying the option -e tcl to man  will  restrict  the  search  to
              pages having an extension of *tcl.

       -i, --ignore-case
              Ignore  case  when  searching  for  manual  pages.   This is the
              default.

       -I, --match-case
              Search for manual pages case-sensitively.

       --regex
              Show all pages with any part of  either  their  names  or  their
              descriptions  matching  each  page argument as a regular expres‐
              sion, as with apropos(1).  Since there is usually no  reasonable
              way  to  pick a "best" page when searching for a regular expres‐
              sion, this option implies -a.

       --wildcard
              Show all pages with any part of  either  their  names  or  their
              descriptions matching each page argument using shell-style wild‐
              cards, as with apropos(1) --wildcard.  The  page  argument  must
              match  the  entire  name or description, or match on word bound‐
              aries in the description.  Since there is usually no  reasonable
              way  to  pick  a "best" page when searching for a wildcard, this
              option implies -a.

       --names-only
              If the --regex or --wildcard option is  used,  match  only  page
              names,  not page descriptions, as with whatis(1).  Otherwise, no
              effect.

       -a, --all
              By default, man will exit after  displaying  the  most  suitable
              manual  page  it finds.  Using this option forces man to display
              all the manual pages with names that match the search criteria.

       -u, --update
              This option causes man to perform an `inode  level'  consistency
              check on its database caches to ensure that they are an accurate
              representation of the filesystem.  It will only  have  a  useful
              effect if man is installed with the setuid bit set.

       --no-subpages
              By default, man will try to interpret pairs of manual page names
              given on the command line as equivalent to a single manual  page
              name  containing  a  hyphen or an underscore.  This supports the
              common pattern of programs that implement a  number  of  subcom‐
              mands,  allowing  them to provide manual pages for each that can
              be accessed using similar syntax as would be used to invoke  the
              subcommands themselves.  For example:

                $ man -aw git diff
                /usr/share/man/man1/git-diff.1.gz

              To disable this behaviour, use the --no-subpages option.

                $ man -aw --no-subpages git diff
                /usr/share/man/man1/git.1.gz
                /usr/share/man/man3/Git.3pm.gz
                /usr/share/man/man1/diff.1.gz

   Controlling formatted output
       -P pager, --pager=pager
              Specify  which  output  pager to use.  By default, man uses less
              -s.  This option overrides the $MANPAGER  environment  variable,
              which  in turn overrides the $PAGER environment variable.  It is
              not used in conjunction with -f or -k.

              The value may be a simple command name or a command  with  argu‐
              ments, and may use shell quoting (backslashes, single quotes, or
              double quotes).  It may not use pipes to connect  multiple  com‐
              mands;  if  you  need that, use a wrapper script, which may take
              the file to display either as an argument or on standard input.

       -r prompt, --prompt=prompt
              If a recent version of less is  used  as  the  pager,  man  will
              attempt  to  set  its  prompt  and  some  sensible options.  The
              default prompt looks like

               Manual page name(sec) line x

              where name denotes the manual page name, sec denotes the section
              it  was  found  under  and  x  the current line number.  This is
              achieved by using the $LESS environment variable.

              Supplying -r with a string  will  override  this  default.   The
              string  may  contain  the text $MAN_PN which will be expanded to
              the name of the current manual page and its  section  name  sur‐
              rounded  by `(' and `)'.  The string used to produce the default
              could be expressed as

              \ Manual\ page\ \$MAN_PN\ ?ltline\ %lt?L/%L.:
              byte\ %bB?s/%s..?\ (END):?pB\ %pB\\%..
              (press h for help or q to quit)

              It is broken into three lines here for the sake  of  readability
              only.   For its meaning see the less(1) manual page.  The prompt
              string is first evaluated by  the  shell.   All  double  quotes,
              back-quotes  and  backslashes in the prompt must be escaped by a
              preceding backslash.  The prompt string may end in an escaped  $
              which  may  be followed by further options for less.  By default
              man sets the -ix8 options.

              If you want to override  man's  prompt  string  processing  com‐
              pletely, use the $MANLESS environment variable described below.

       -7, --ascii
              When  viewing a pure ascii(7) manual page on a 7 bit terminal or
              terminal emulator, some characters  may  not  display  correctly
              when  using  the  latin1(7)  device  description with GNU nroff.
              This option allows pure ascii manual pages to  be  displayed  in
              ascii  with the latin1 device.  It will not translate any latin1
              text.  The following table  shows  the  translations  performed:
              some  parts  of it may only be displayed properly when using GNU
              nroff's latin1(7) device.


              Description        Octal   latin1   ascii
              ──────────────────────────────────────────
              continuation        255      ‐        -
              hyphen
              bullet   (middle    267      ·        o
              dot)
              acute accent        264      ´        '
              multiplication      327      ×        x
              sign

              If  the  latin1  column displays correctly, your terminal may be
              set up for latin1 characters and this option is  not  necessary.
              If  the  latin1 and ascii columns are identical, you are reading
              this page using this option or man  did  not  format  this  page
              using  the  latin1  device description.  If the latin1 column is
              missing or corrupt, you may need to view manual pages with  this
              option.

              This  option is ignored when using options -t, -H, -T, or -Z and
              may be useless for nroff other than GNU's.

       -E encoding, --encoding=encoding
              Generate output for a character encoding other than the default.
              For backward compatibility, encoding may be an nroff device such
              as ascii, latin1, or utf8 as well as a true  character  encoding
              such as UTF-8.

       --no-hyphenation, --nh
              Normally, nroff will automatically hyphenate text at line breaks
              even in words that do not contain hyphens, if it is necessary to
              do  so  to  lay  out  words on a line without excessive spacing.
              This option disables automatic hyphenation, so words  will  only
              be hyphenated if they already contain hyphens.

              If  you  are  writing  a  manual page and simply want to prevent
              nroff from hyphenating a word at an inappropriate point, do  not
              use  this  option,  but consult the nroff documentation instead;
              for instance, you can put "\%" inside a word to indicate that it
              may  be  hyphenated at that point, or put "\%" at the start of a
              word to prevent it from being hyphenated.

       --no-justification, --nj
              Normally, nroff will automatically justify text to both margins.
              This  option disables full justification, leaving justified only
              to the left margin, sometimes called "ragged-right" text.

              If you are writing a manual page  and  simply  want  to  prevent
              nroff  from  justifying  certain  paragraphs,  do  not  use this
              option,  but  consult  the  nroff  documentation  instead;   for
              instance,  you  can  use  the  ".na",  ".nf",  ".fi",  and ".ad"
              requests to temporarily disable adjusting and filling.

       -p string, --preprocessor=string
              Specify the sequence of preprocessors to  run  before  nroff  or
              troff/groff.  Not all installations will have a full set of pre‐
              processors.  Some of the preprocessors and the letters  used  to
              designate  them are: eqn (e), grap (g), pic (p), tbl (t), vgrind
              (v), refer (r).  This option overrides the $MANROFFSEQ  environ‐
              ment  variable.   zsoelim  is  always run as the very first pre‐
              processor.

       -t, --troff
              Use groff -mandoc to format the manual  page  to  stdout.   This
              option is not required in conjunction with -H, -T, or -Z.

       -T[device], --troff-device[=device]
              This option is used to change groff (or possibly troff's) output
              to be suitable for a device other than the default.  It  implies
              -t.   Examples  (provided  with Groff-1.17) include dvi, latin1,
              ps, utf8, X75 and X100.

       -H[browser], --html[=browser]
              This option will cause groff to produce HTML  output,  and  will
              display  that output in a web browser.  The choice of browser is
              determined by the optional browser argument if one is  provided,
              by  the  $BROWSER  environment  variable,  or  by a compile-time
              default if that is unset (usually lynx).   This  option  implies
              -t, and will only work with GNU troff.

       -X[dpi], --gxditview[=dpi]
              This  option  displays the output of groff in a graphical window
              using the gxditview program.  The dpi (dots per inch) may be 75,
              75-12,  100, or 100-12, defaulting to 75; the -12 variants use a
              12-point base font.   This  option  implies  -T  with  the  X75,
              X75-12, X100, or X100-12 device respectively.

       -Z, --ditroff
              groff  will run troff and then use an appropriate post-processor
              to produce output suitable for  the  chosen  device.   If  groff
              -mandoc  is  groff, this option is passed to groff and will sup‐
              press the use of a post-processor.  It implies -t.

   Getting help
       -?, --help
              Print a help message and exit.

       --usage
              Print a short usage message and exit.

       -V, --version
              Display version information.

EXIT STATUS
       0      Successful program execution.

       1      Usage, syntax or configuration file error.

       2      Operational error.

       3      A child process returned a non-zero exit status.

       16     At least one of the pages/files/keywords didn't exist or  wasn't
              matched.

ENVIRONMENT
       MANPATH
              If  $MANPATH is set, its value is used as the path to search for
              manual pages.

       MANROFFOPT
              The contents of $MANROFFOPT are added to the command line  every
              time man invokes the formatter (nroff, troff, or groff).

       MANROFFSEQ
              If $MANROFFSEQ is set, its value is used to determine the set of
              preprocessors to pass each manual  page  through.   The  default
              preprocessor list is system dependent.

       MANSECT
              If  $MANSECT is set, its value is a colon-delimited list of sec‐
              tions and it is used  to  determine  which  manual  sections  to
              search and in what order.

       MANPAGER, PAGER
              If $MANPAGER or $PAGER is set ($MANPAGER is used in preference),
              its value is used as the name of the program used to display the
              manual page.  By default, less -s is used.

              The  value  may be a simple command name or a command with argu‐
              ments, and may use shell quoting (backslashes, single quotes, or
              double  quotes).   It may not use pipes to connect multiple com‐
              mands; if you need that, use a wrapper script,  which  may  take
              the file to display either as an argument or on standard input.

       MANLESS
              If  $MANLESS  is set, man will not perform any of its usual pro‐
              cessing to set up a prompt string for the less pager.   Instead,
              the  value  of $MANLESS will be copied verbatim into $LESS.  For
              example, if you want to set the prompt string unconditionally to
              “my prompt string”, set $MANLESS to ‘-Psmy prompt string’.

       BROWSER
              If  $BROWSER is set, its value is a colon-delimited list of com‐
              mands, each of which in turn is used  to  try  to  start  a  web
              browser  for  man  --html.  In each command, %s is replaced by a
              filename containing the HTML output from groff, %%  is  replaced
              by a single percent sign (%), and %c is replaced by a colon (:).

       SYSTEM If  $SYSTEM  is  set,  it will have the same effect as if it had
              been specified as the argument to the -m option.

       MANOPT If $MANOPT is set, it will be parsed prior to man's command line
              and  is expected to be in a similar format.  As all of the other
              man specific environment variables can be expressed  as  command
              line  options,  and  are  thus  candidates for being included in
              $MANOPT it is expected that they will become obsolete.  N.B. All
              spaces  that  should be interpreted as part of an option's argu‐
              ment must be escaped.

       MANWIDTH
              If $MANWIDTH is set, its value is used as the  line  length  for
              which  manual pages should be formatted.  If it is not set, man‐
              ual pages will be formatted with a line  length  appropriate  to
              the  current terminal (using an ioctl(2) if available, the value
              of $COLUMNS, or falling back to  80  characters  if  neither  is
              available).   Cat pages will only be saved when the default for‐
              matting can be used, that is when the terminal  line  length  is
              between 66 and 80 characters.

       MAN_KEEP_FORMATTING
              Normally,  when output is not being directed to a terminal (such
              as to a file or a pipe), formatting characters are discarded  to
              make  it  easier to read the result without special tools.  How‐
              ever, if $MAN_KEEP_FORMATTING is set  to  any  non-empty  value,
              these  formatting  characters  are retained.  This may be useful
              for wrappers around man that can  interpret  formatting  charac‐
              ters.

       MAN_KEEP_STDERR
              Normally,  when  output is being directed to a terminal (usually
              to a pager), any error output from the command used  to  produce
              formatted  versions of manual pages is discarded to avoid inter‐
              fering with the pager's display.  Programs such as  groff  often
              produce  relatively  minor  error  messages  about typographical
              problems such as poor alignment, which are unsightly and  gener‐
              ally  confusing when displayed along with the manual page.  How‐
              ever,  some  users   want   to   see   them   anyway,   so,   if
              $MAN_KEEP_STDERR  is  set  to  any non-empty value, error output
              will be displayed as usual.

       LANG, LC_MESSAGES
              Depending on system and implementation, either or both of  $LANG
              and  $LC_MESSAGES  will  be interrogated for the current message
              locale.  man will display its messages in that locale (if avail‐
              able).  See setlocale(3) for precise details.

FILES
       /etc/man_db.conf
              man-db configuration file.

       /usr/share/man
              A global manual page hierarchy.

       /usr/share/man/index.(bt|db|dir|pag)
              A traditional global index database cache.

       /var/cache/man/index.(bt|db|dir|pag)
              An FHS compliant global index database cache.

SEE ALSO
       apropos(1),   groff(1),   less(1),   manpath(1),   nroff(1),  troff(1),
       whatis(1), zsoelim(1), setlocale(3), manpath(5),  ascii(7),  latin1(7),
       man(7), catman(8), mandb(8), the man-db package manual, FSSTND

HISTORY
       1990, 1991 - Originally written by John W. Eaton (jwe@che.utexas.edu).

       Dec 23 1992: Rik Faith (faith@cs.unc.edu) applied bug fixes supplied by
       Willem Kasdorp (wkasdo@nikhefk.nikef.nl).

       30th April 1994 - 23rd February 2000: Wilf. (G.Wilford@ee.surrey.ac.uk)
       has been developing and maintaining this package with the help of a few
       dedicated people.

       30th  October  1996  -  30th  March  2001:   Fabrizio   Polacco   <fpo‐
       lacco@debian.org>  maintained  and enhanced this package for the Debian
       project, with the help of all the community.

       31st March 2001 - present day: Colin  Watson  <cjwatson@debian.org>  is
       now developing and maintaining man-db.



2.6.3                             2012-09-17                            MAN(1)

Tip

Raccourcis dans l’aide:

  • /color : pour chercher le terme ‘color’.

  • n : (next) pour chercher la prochaine occurrence de ‘truc’.

  • p: (previous) pour chercher l’occurrence précédente de ‘truc’.

  • q : pour quitter l’aide.

Zoom sur la commande ls#

La commande ls et ses arguments#

La commande ls peut prendre un certain nombre d’arguments.

Parmis les arguments principaux:

  • -l (long/lot) donne beaucoup d’informations sur les fichiers.

  • -a (all) montre tous les fichiers y compris ceux qui sont cachés*.

  • -t (time) trie par date de modification.

  • -h (human-readable) affiche les tailles des fichiers en unités lisibles

  • -r (reverse) inverse l’ordre du tri.

On peut combiner les arguments : ls -l --all

On peut fusionner les arguments (au format court) : ls -la

Sous Linux les noms des fichiers cachés commencent par un point (e.g ‘.bashrc’).

La commande ls et ses arguments#

# On se déplace dans le dossier
cd /shared/bank/homo_sapiens/hg38/fasta   
# On liste les fichiers
ls   
hg38.fa  hg38.fa.fai
# Information détaillée sur les fichiers (taille, date modif,...)
ls -l 
total 3196788
-rwxrwxr-x 1 glecorguille bank_admin 3273481150 Jan 16  2014 hg38.fa
-rwxrwxr-x 1 glecorguille bank_admin      19381 Nov 21  2016 hg38.fa.fai
# Vue détaillée des fichiers et tailles en Ko,Mo,Go,To... 
ls -lh
total 3.1G
-rwxrwxr-x 1 glecorguille bank_admin 3.1G Jan 16  2014 hg38.fa
-rwxrwxr-x 1 glecorguille bank_admin  19K Nov 21  2016 hg38.fa.fai
# Vue détaillée des fichiers, tailles en Ko,Mo,Go,To…, tri par date
ls -tlh
total 3.1G
-rwxrwxr-x 1 glecorguille bank_admin  19K Nov 21  2016 hg38.fa.fai
-rwxrwxr-x 1 glecorguille bank_admin 3.1G Jan 16  2014 hg38.fa
# Vue détaillée des fichiers, tailles en Ko,Mo,Go,To…, tri par date
# du plus ancien au plus récent
ls -rtlh
total 3.1G
-rwxrwxr-x 1 glecorguille bank_admin 3.1G Jan 16  2014 hg38.fa
-rwxrwxr-x 1 glecorguille bank_admin  19K Nov 21  2016 hg38.fa.fai

Note

  • ATTENTION aux espaces, nécessaires entre la commande et ses arguments. La commande ls-l n’existe pas !

  • Le comportement par défaut de ls est de trier par ordre alphabétique en tenant compte de la casse (ie. majuscule minuscule).