Filesystem

On Unix systems everything is a file.

Filesystem structure #

A path on a filesystem is noted as a string starting with a /

Example:

/home/user/Documents/mydocument.odt

~ indicates the home directory of the current user (also in $HOME) . the current directory .. the parent directory

Listing files #

ls [directory]: lists files inside a directory, often you use ls without any arguments to show the files in the current directory

-l shows list with permissions are file sizes.
-a shows 'hidden' files often also called dotfiles which are files starting with a dot '.'
-h shows file sizes in a humman readable format instead of the byte count

Tip: you can combine these flags like this:

ls -lah

Common directories #

ls /

/ filesystem root
/bin program binaries
/dev devices
/etc configuration files
/home home directories of normal users
/mnt mountpoints
/opt optional software
/proc virtual filesystem to access kernel data
/root home directory of the root user
/run runtime data, often for daemons (lost after reboot)
/srv services data, often for web services
/sys virtual filesystem for system devices
/tmp temorary data (lost after reboot)
/usr Unix System Resources, files that generally not change
/var variable data, files that frequently change like log files

Directory #

cd Change Directory

pwd shows current directory

Creating files #

touch [filename] creates an empty file

Reading files #

cat head tail

Editing files #

You can edit files on the terminal using a terminal text editor like Vi(m) or Nano. Often vi,vim and/or nano are installed by default on many linux distros.

Moving files #

cp for copy
mv for move/rename
rm for remove