GNU/Linux Getting started with GNU/Linux Basic Linux Utilities
Example
Linux has a command for almost any tasks and most of them are intuitive and easily interpreted.
Getting Help in Linux
| Command | Usability |
|---|---|
man <name> | Read the manual page of <name>. |
man <section> <name> | Read the manual page of <name>, related to the given section. |
man -k <editor> | Output all the software whose man pages contain <editor> keyword. |
man -K <keyword> | Outputs all man pages containing <keyword> within them. |
apropos <editor> | Output all the applications whose one line description matches the word editor. When not able to recall the name of the application, use this command. |
help | In Bash shell, this will display the list of all available bash commands. |
help <name> | In Bash shell, this will display the info about the <name> bash command. |
info <name> | View all the information about <name>. |
dpkg -l | Output a list of all installed packages on a Debian-based system. |
dpkg -L packageName | Will list out the files installed and path details for a given package on Debian. |
dpkg -l | grep -i <edit> | Return all .deb installed packages with <edit> irrespective of cases. |
less /var/lib/dpkg/available | Return descriptions of all available packages. |
whatis vim | List a one-line description of vim. |
<command-name> --help | Display usage information about the <tool-name>. Sometimes command -h also works, but not for all commands. |
User identification and who is who in Linux world
| Command | Usability |
|---|---|
hostname | Display hostname of the system. |
hostname -f | Displays Fully Qualified Domain Name (FQDN) of the system. |
passwd | Change password of current user. |
whoami | Username of the users logged in at the terminal. |
who | List of all the users currently logged in as a user. |
w | Display current system status, time, duration, list of users currently logged in on system and other user information. |
last | Who recently used the system. |
last root | When was the last time root logged in as user. |
lastb | Shows all bad login attempts into the system. |
chmod | Changing permissions - read,write,execute of a file or directory. |
Process related information
| Command | Usability |
|---|---|
top | List all processes sorted by their current system resource usage. Displays a continually updated display of processes (By default 3 seconds). Use q key to exit top. |
ps | List processes currently running on current shell session |
ps -u root | List all of the processes and commands root is running |
ps aux | List all the processes by all users on the current system |
