Skip to Content
DocsLinuxHelp Command

Help Command

When you need assistance with Linux commands, there are several built-in help options available that will provide you a quick reference or detailed information about command usage.

Using the whatis Command

The whatis command provides a brief description of a command. To use it, simply type whatis followed by the command name. For example:

karchunt@kcserver:~$ whatis ls
ls (1)               - list directory contents

Using the man Command

The man command displays the manual pages for a command, providing detailed information about its usage, options, and examples. To access the manual for a command, type man followed by the command name. For example:

karchunt@kcserver:~$ 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 .
...

Using the --help Option

Most Linux commands support the --help option, which provides a summary of the command’s usage and available options. To use it, type the command followed by --help or -h. For example:

karchunt@kcserver:~$ ls --help
Usage: ls [OPTION]... [FILE]...
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
...

Searching with apropos

The apropos command searches the manual page names and descriptions for a specified keyword. This is useful when you are unsure of the exact command name. For example:

karchunt@kcserver:~$ apropos copy
cp (1)               - copy files and directories
cpgr (8)             - copy with locking the given file to the password or group file
cppw (8)             - copy with locking the given file to the password or group file
dd (1)               - convert and copy a file
debconf-copydb (1)   - copy a debconf database
git-checkout-index (1) - Copy files from the index to the working tree
install (1)          - copy files and set attributes
objcopy (1)          - copy and translate object files
rsync (1)            - a fast, versatile, remote (and local) file-copying tool
scp (1)              - OpenSSH secure file copy
ssh-copy-id (1)      - use locally available keys to authorise logins on a remote machine
string_copying (7)   - copying strings and character sequences
x86_64-linux-gnu-objcopy (1) - copy and translate object files
Last updated on
Basic CommandsBash Shell