Moltes vegades et trobaràs que no saps exactament on van els atributs d’una comanda o no saps ben bé com s’utilitza. Pots utilitzar Internet i buscar-ho a alguna pàgina web, però a vegades és més ràpid utilitzar directament els recursos que ofereix el sistema.

Man

Cada eina té una pàgina de descripció i ajuda. Amb la comanda man podràs llegir-la fàcilment:

nadki@debian:~$ 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 specified.

       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
              with -l, scale sizes by SIZE when printing them; e.g., '--block-size=M'; 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]
              color the output WHEN; more info below

Info

Molt similar a la comanda man. Et permet llegir documentació de la comanda. S’ha d’instal·lar a través d’APT.

nadki@debian:~$ info ls
Next: dir invocation,  Up: Directory listing

10.1 ‘ls’: List directory contents
==================================

The ‘ls’ program lists information about files (of any type, including
directories).  Options and file arguments can be intermixed arbitrarily,
as usual.  Later options override earlier options that are incompatible.

   For non-option command-line arguments that are directories, by
default ‘ls’ lists the contents of directories, not recursively, and
omitting files with names beginning with ‘.’.  For other non-option
arguments, by default ‘ls’ lists just the file name.  If no non-option
argument is specified, ‘ls’ operates on the current directory, acting as
if it had been invoked with a single argument of ‘.’.

   By default, the output is sorted alphabetically, according to the
locale settings in effect.(1)  If standard output is a terminal, the
output is in columns (sorted vertically) and control characters are
output as question marks; otherwise, the output is listed one per line
and control characters are output as-is.

   Because ‘ls’ is such a fundamental program, it has accumulated many
options over the years.  They are described in the subsections below;
within each section, options are listed alphabetically (ignoring case).
The division of options into the subsections is not absolute, since some
options affect more than one aspect of ‘ls’’s operation.

   Exit status:

     0 success
     1 minor problems  (e.g., failure to access a file or directory not
[...]

Apropos

Si no saps exactament quina eina utilitzar, pots executar apropos, que et recomana comandes que la descripció coincideix amb el que busques:

nadki@debian:~$ apropos "copy file"
cp (1)               - copy files and directories
cpio (1)             - copy files to and from archives
git-checkout-index (1) - Copy files from the index to the working tree
install (1)          - copy files and set attributes
ntfscp (8)           - copy file to an NTFS volume.