Main GNU/Linux commands to know when you're a beginner

I will put here the main commands to know in a GNU/Linux environment when you start with it.

PWD - Where am I?

The pwd command

To know in which path you are, you can use the pwd command.

user01@host:~$ pwd
/home/user01

Here, we can see that we are inside the user01 home directory.

Linux Directory Structure

Remember the Linux path structure (thanks to Wikipedia) and its Windows OS equivalence.

CD - Change directory

Change working directory, we can use the cd (change directory) command.

• Going to /tmp directory :

user@host:~$ cd /tmp

CP - Copy a file or a directory

Files

To copy a file or a directory we can use cp.

• Copy my_file to my_file.bak :

user@host:~$ cp my_file my_file.bak

• Copy my_file to a different directory :

user@host:~$ cp my_file /tmp/

• Copy multiple files to a directory :

user@host:~$ cp my_file my_file.bak -t /tmp/

Directories

• Copy a directory (-r : recursively) :

user@host:~$ cp -r my_directory my_directory.bak

MKDIR - Create new directory

• Create a directory :

user@host:~$ mkdir my_directory

MV - Move a file or a directory

Files

To move a file or a directory we can use mv.

• Move my_file to my_file.bak :

user@host:~$ mv my_file my_file.bak

• Move my_file to a different directory :

user@host:~$ mv my_file /tmp/

• Move multiple files to a directory :

user@host:~$ mv my_file my_file.bak -t /tmp/

Directories

• Move a directory :

user@host:~$ mv my_directory my_directory.bak

LS - Show files and directories

To list files we can use ls.

• List directories and files from current location :

user@host:~$ ls
my_directory  my_directory.bak  my_file  my_file.bak

• List directories and files from current location with details informations (size, owners, right etc..) :

user@host:~$ ls -l
total 8192
drwxr-xr-x 2 user user      40 25 oct.  12:12 my_directory
drwxr-xr-x 2 user user      40 25 oct.  12:12 my_directory.bak
-rw-r--r-- 1 user user  8388608 25 oct.  12:12 my_file
-rw-r--r-- 1 user user        0 25 oct.  12:12 my_file.bak

You can see the d indicator for directories.

• We can add -h option to have human readable sizes :

user@host:~$ ls -lh
total 8,0M
drwxr-xr-x 2 user user   40 25 oct.  12:12 my_directory
drwxr-xr-x 2 user user   40 25 oct.  12:12 my_directory.bak
-rw-r--r-- 1 user user 8,0M 25 oct.  13:22 my_file
-rw-r--r-- 1 user user    0 25 oct.  12:12 my_file.bak

RM - Remove files or directory

To remove files or directories we can use the rm command.

Be aware that there is no Recycle Bin, so once you remove files or directories, they'll be forever lost.

Files

• Here we remove the my_file file :

user@host:~$ rm my_file

Directories

• To remove directories we use the -r (for recursive) argument :

user@host:~$ rm -r my_directory

TAIL - Output the last part of files

Particulary useful when you want to watch real time logs.

user@host:~$ tail -f /var/log/syslog

FIND - Find files or directories

• Example here if we want to search inside /home/user for every files and folders which include "std" in their names :

user@host:~$ find /home/user -iname '*std*'
/home/user/std
/home/user/anything_std_want
/home/user/easy_std_way
/home/user/easy_std
/home/user/anemia_std