Linux terminal basics

Viewing Directories & Files

to find which directory you are currently in:

scribbles@testDesktop:~$ pwd
/home/scribbles
scribbles@testDesktop:~$

to list contents of current directory (this example shows the home directory on a newly installed Ubuntu desktop virtual machine):

scribbles@testDesktop:~$ ls
Desktop  Documents  Downloads  Music  Pictures  Public  snap  Templates  thinclient_drives  Videos
scribbles@testDesktop:~$

this commmand only shows the names of the directories (& would show filenames if there were any) all in one line & with no other information.

adding the ‘-l’ parameter to the command we get a ’long listing’ of the contents, as shown here:

scribbles@testDesktop:~$ ls -l
total 36
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Desktop
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Documents
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Downloads
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Music
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Pictures
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Public
drwx------ 3 scribbles scribbles 4096 Aug 30 16:51 snap
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Templates
drwx------ 1 scribbles scribbles    0 Aug 31 15:03 thinclient_drives
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Videos

This gives much more information. The first row gives the total number of blocks on disk used by the contents displayed (the explanation of blocks is beyond the scope of this post). Whilst the other rows show, from left to right:

  • the permissions for each directory and/or file
  • the number of items - this is only really useful for directories as files will always show 1
  • the owner
  • the group
  • the size for files (directories always show 4096)
  • the last modified date and time
  • the name

Any file whose name starts with a ‘.’ is automatically hidden. To include these files in our listing, we use the ‘-a’ parameter. This parameter can be combined the -l and entereed as ’ls -la’ as shown here:

scribbles@testDesktop:~$ ls -la
total 140
drwxr-x--- 17 scribbles scribbles  4096 Aug 31 15:11 .
drwxr-xr-x  3 root      root       4096 Aug 30 16:46 ..
-rw-------  1 scribbles scribbles   585 Aug 31 13:56 .bash_history
-rw-r--r--  1 scribbles scribbles   220 Aug 30 16:46 .bash_logout
-rw-r--r--  1 scribbles scribbles  3771 Aug 30 16:46 .bashrc
drwx------ 12 scribbles scribbles  4096 Aug 30 17:22 .cache
drwx------ 11 scribbles scribbles  4096 Aug 31 14:51 .config
drwxr-xr-x  2 scribbles scribbles  4096 Aug 30 16:51 Desktop
drwxr-xr-x  2 scribbles scribbles  4096 Aug 30 16:51 Documents
drwxr-xr-x  2 scribbles scribbles  4096 Aug 30 16:51 Downloads
-rw-------  1 scribbles scribbles    20 Aug 31 15:11 .lesshst
drwx------  3 scribbles scribbles  4096 Aug 30 16:51 .local
drwxr-xr-x  2 scribbles scribbles  4096 Aug 30 16:51 Music
drwxrwxrwt  2 scribbles scribbles  4096 Aug 31 15:03 .pcsc10
drwxr-xr-x  2 scribbles scribbles  4096 Aug 30 16:51 Pictures
-rw-r--r--  1 scribbles scribbles   807 Aug 30 16:46 .profile
drwxr-xr-x  2 scribbles scribbles  4096 Aug 30 16:51 Public
drwx------  3 scribbles scribbles  4096 Aug 30 16:51 snap
drwx------  2 scribbles scribbles  4096 Aug 30 17:22 .ssh
-rw-r--r--  1 scribbles scribbles     0 Aug 30 16:53 .sudo_as_admin_successful
drwxr-xr-x  2 scribbles scribbles  4096 Aug 30 16:51 Templates
drwx------  1 scribbles scribbles     0 Aug 31 15:03 thinclient_drives
drwxr-xr-x  2 scribbles scribbles  4096 Aug 30 16:51 Videos
-rw-------  1 scribbles scribbles    57 Aug 31 14:54 .Xauthority
-rw-r--r--  1 scribbles scribbles 25801 Aug 31 15:48 .xorgxrdp.10.log
-rw-r--r--  1 scribbles scribbles 19790 Aug 31 14:53 .xorgxrdp.10.log.old
-rw-------  1 scribbles scribbles  1263 Aug 31 14:54 .xsession-errors

Creating Directories & Files

to create a new file in the current directory use ’touch’ followed by the desired file name:

scribbles@testDesktop:~$ touch newfile
scribbles@testDesktop:~$ ls -l
total 40
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Desktop
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Documents
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Downloads
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Music
-rw-rw-r-- 1 scribbles scribbles    0 Sep  1 14:18 newfile
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Pictures
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Public
drwx------ 3 scribbles scribbles 4096 Aug 30 16:51 snap
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Templates
drwxrwxr-t 2 scribbles scribbles 4096 Aug 30 17:13 thinclient_drives
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Videos
scribbles@testDesktop:~$

to create a new directory in the current directory use ‘mkdir’ followed the desired directory name:

scribbles@testDesktop:~$ mkdir newdirectory
scribbles@testDesktop:~$ ls -l
total 44
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Desktop
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Documents
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Downloads
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Music
drwxrwxr-x 2 scribbles scribbles 4096 Sep  1 14:20 newdirectory
-rw-rw-r-- 1 scribbles scribbles    0 Sep  1 14:18 newfile
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Pictures
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Public
drwx------ 3 scribbles scribbles 4096 Aug 30 16:51 snap
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Templates
drwxrwxr-t 2 scribbles scribbles 4096 Aug 30 17:13 thinclient_drives
drwxr-xr-x 2 scribbles scribbles 4096 Aug 30 16:51 Videos
scribbles@testDesktop:~$

to list contents of another directory append the directory path to the ’ls -l’ command - this can be done using a relative path (which means relative to the current directory):

scribbles@testDesktop:~$ ls -l newdirectory/
total 0
scribbles@testDesktop:~$

or using an absolute path (relative to the root ‘/’ directory):

scribbles@testDesktop:~$ ls -l /home/scribbles/newdirectory/
total 0
scribbles@testDesktop:~$

to add a new file (or directory) to another directory works in pretty much the same way:

scribbles@testDesktop:~$ touch newdirectory/newfile2
scribbles@testDesktop:~$ mkdir newdirectory/newdirectory2
scribbles@testDesktop:~$ ls -l newdirectory/
total 4
drwxrwxr-x 2 scribbles scribbles 4096 Sep  1 14:27 newdirectory2
-rw-rw-r-- 1 scribbles scribbles    0 Sep  1 14:27 newfile2
scribbles@testDesktop:~$

Modifying Directories & Files

to rename a directory or file use the ‘mv’ command:

scribbles@testDesktop:~$ cd newdirectory/
scribbles@testDesktop:~/newdirectory$ ls -l
total 4
drwxrwxr-x 2 scribbles scribbles 4096 Sep  1 14:27 newdirectory2
-rw-rw-r-- 1 scribbles scribbles    0 Sep  1 14:27 newfile2
scribbles@testDesktop:~/newdirectory$ mv newfile2 newfile2.1
scribbles@testDesktop:~/newdirectory$ mv newdirectory2/ newdirectory2.1
scribbles@testDesktop:~/newdirectory$ ls -l
total 4
drwxrwxr-x 2 scribbles scribbles 4096 Sep  1 14:27 newdirectory2.1
-rw-rw-r-- 1 scribbles scribbles    0 Sep  1 14:27 newfile2.1
scribbles@testDesktop:~/newdirectory$

There are differences when making copies of files and directories due to directories potentially containing files and/or other directories.

to create copy a file use the ‘cp’ command:

scribbles@testDesktop:~/newdirectory$ cp newfile2.1 otherfile2.1
scribbles@testDesktop:~/newdirectory$ ls -l
total 4
drwxrwxr-x 2 scribbles scribbles 4096 Sep  1 14:27 newdirectory2.1
-rw-rw-r-- 1 scribbles scribbles    0 Sep  1 14:27 newfile2.1
-rw-rw-r-- 1 scribbles scribbles    0 Sep  1 14:36 otherfile2.1
scribbles@testDesktop:~/newdirectory$

if the directory contains any other files or directories, use the ‘-r’ parameter (recursive - includes all child contents of the parent):

scribbles@testDesktop:~/newdirectory$ ls -l newdirectory2.1/
total 0
-rw-rw-r-- 1 scribbles scribbles 0 Sep  1 14:36 otherfile2.1
scribbles@testDesktop:~/newdirectory$ cp newdirectory2.1/ otherdirectory2.1
cp: -r not specified; omitting directory 'newdirectory2.1/'
scribbles@testDesktop:~/newdirectory$ cp -r newdirectory2.1/ otherdirectory2.1
scribbles@testDesktop:~/newdirectory$ ls -l
total 8
drwxrwxr-x 2 scribbles scribbles 4096 Sep  1 14:36 newdirectory2.1
-rw-rw-r-- 1 scribbles scribbles    0 Sep  1 14:27 newfile2.1
drwxrwxr-x 2 scribbles scribbles 4096 Sep  1 14:39 otherdirectory2.1
scribbles@testDesktop:~/newdirectory$ ls -l otherdirectory2.1/
total 0
-rw-rw-r-- 1 scribbles scribbles 0 Sep  1 14:39 otherfile2.1
scribbles@testDesktop:~/newdirectory$ ls -l newdirectory2.1/
total 0
-rw-rw-r-- 1 scribbles scribbles 0 Sep  1 14:36 otherfile2.1
scribbles@testDesktop:~/newdirectory$

Reading and adding content to Files

Aside from using file editors such as nano or vim, it can often be useful to either read out or add to the content of a file directly in the terminal using ‘cat’

Note that the ‘>’ symbol will overwrite all contents of the file.

adding some text to an empty file:

scribbles@testDesktop:~/newdirectory$ ls -l
total 0
-rw-rw-r-- 1 scribbles scribbles 0 Sep  1 14:27 newfile
scribbles@testDesktop:~/newdirectory$ cat newfile
scribbles@testDesktop:~/newdirectory$ echo 'this is the first line' > newfile
scribbles@testDesktop:~/newdirectory$ cat newfile
this is the first line
scribbles@testDesktop:~/newdirectory$

using ‘»’ to append text to the file:

scribbles@testDesktop:~/newdirectory$ cat newfile
this is the first line
scribbles@testDesktop:~/newdirectory$ echo 'this is the second line' >> newfile
scribbles@testDesktop:~/newdirectory$ cat newfile
this is the first line
this is the second line
scribbles@testDesktop:~/newdirectory$