Basic Linux/Unix commands
In this document, we go through some of the most basic Linux commands. These commands can be used in the shell (the command line terminal) to get full use of your remote server. Most of these commands will be compatible with all UNIX OSes. However, depending on the version, the arguments (the parameters after the basic command) used may change.
cd: Change directory
cd allows you to change the directory you are in on your shell.
For example, you are in your personal directory (home) and you want to navigate to the directory where your log files are (/var/log). Enter the following command:
You are now in the
ls: List the content of a directory
This command allows you to display all the contents of a directory.
You are still in the
/var/log directory, and you want to see everything it contains. Enter the
ls command. A list of the contents displays as output:
alternatives.log alternatives.log.7.gz apport.log.5.gz auth.log.4.gz dmesg.0 dpkg.log.3.gz fontconfig.log kern.log.3.gz pm-powersave.log.4.gz syslog.2.gz upstartalternatives.log.1 alternatives.log.8.gz apport.log.6.gz boot.log dmesg.1.gz dpkg.log.4.gz fsck kern.log.4.gz pm-suspend.log syslog.3.gz wtmpalternatives.log.10.gz alternatives.log.9.gz apport.log.7.gz bootstrap.log dmesg.2.gz dpkg.log.5.gz gpu-manager.log lastlog pm-suspend.log.1 syslog.4.gz wtmp.1
You can also perform a
ls on another folder:
To get a more detailed view of the files in a directory, type
ls -l, or use the abbreviated command
ll. This displays additional details such as file permissions, dates and sizes.
rm: Remove (delete) folders and files
To delete data, you need the command
rm followed by the name of the file you want to delete:
To delete folders as opposed to files, you need to add the
rm -r myFolder
This will recursively remove all files and content in the folder, and the folder itself
To force a deletion, use
rm -rf myFolder. Pay attention when using this command. A mistake can delete critial data without asking you for confirmation.
man: User manual
In Linux everything is documented! If you want to know how a certain program works, or want to know all its possibilities,
man will give you the answer.
The usage is pretty simple:
man ls will display all the details about the
ls command we saw previously.
nano: File editor
At some point, you will probably need to edit a text file using the command line. The most simple way to do this is via the
nano editor. Type
nano followed by the name of the file you want to edit (if you are in the same directory as the file) or the path to the file (if the file is in another directory):
The nano text editor displays, and you can make your edits. When you have finished, terminate nano by pressing the keys
CTRL + X. If you made any changes, you will be prompted to save them.
Once you have finished to edit your file, terminate nano by pressing the keys: ”CTRL + X”
If you made any changes, you will be asked to save them.