Bash intermediate tutorial

Getting To know the Terminal

Command options

Most linux utilities and commands take options tat modify the behaviour of the output, here are some examples

Command

ls -l

This will cause the ls command to print the contents of a directory in long format. This will give output of this form:

[asesma@comp32 test]$ ls -l
total 4776
-rw-rw-r--  1 asesma asesma   20480 Aug  1  2013 automated-0.1.b-alpha.tgz
-rw-rw-r--  1 asesma asesma      55 May  7  2013 bands.in
-rw-rw-r--  1 asesma asesma   30847 May  7  2013 bn.ps
drwxrwxr-x 38 asesma asesma    4096 May  7  2013 BN.save
-rw-r--r--  1 asesma asesma  306486 May  7  2013 B.pbe-n-van_ak.UPF
-rw-r--r--  1 asesma asesma  270792 May  7  2013 N.pbe-van_ak.UPF
-rw-rw-r--  1 asesma asesma      55 Apr 25 11:54 silicon.in
drwxrwxr-x  2 asesma asesma    4096 Oct 28 17:10 test

The output is split into columns giving various pieces of information, this includes, permissions in the first column, the ownership, then sizes, then a timestamp of the modification/creation date followed by the name.

Command

cp  -r arg1 arg2

The cp command will normally not copy a directory, unless the -r option is passed in this case it will copy the arg1 directory to the arg2 name.

Command

cat file

The cat command is used to show the contents of a text file. Example

[asesma@comp32 test]$ cat bands.in 
&bands
    filband = 'bands.dat',
    prefix = 'BN'
/ 
[asesma@comp32 test]$

This shows that the bands.in has 4 lines of text in it. The cat command can show line numbers if they are needed:

&bands
  filband = 'bands.dat',
    prefix = 'BN'
/

Command

clear

This clears the screen.

Command

rm -r

This command removes a directory

Vi basic commands

How to create a file named new

vi new

Then press i to be in INSERT MODE in order to start typing.

After typing you will have to save. Press Esc and type

 :

Type this

wq  or  x

to save the changes and quit, or,

q!

to quit without saving (if there is same changes done), or,

q

to quit without saving (if there no changes done).

To view the exiting file, type vi followed by the file name, and press Enter example

vi new