Variables and environment variables

1. Get the Process ID number:

(assuming that an application called Gedit is running, you can use the Pgrep command to get the gedit process ID)

$ pgrep gedit12501

2. View environment variables for runtime processes

cat/proc/$PID/environ

3. Get the string length

length=${#var}

4. Identify the shell that is currently in use

Echo $SHELLecho

5. Check if you are a superuser

The UUID is an important environment variable that can be used to check whether the current script is running as a superuser or as a normal user

If [$UID-ne 0]:then echo Non root user. Please run as Root.else echo Root Userfi

6. Modify bash prompt string ([email protected]:~$)

You can use the PS1 environment variable to customize the hint text, the default shell hint text is set in the file ~/.BASHRC, view a row by the following command

$ cat ~/.BASHRC |grep PS1 ps1= ' ${debian_chroot:+ ($debian _chroot)}\[email protected]\h:\w\$ '

If you want to set a custom prompt string

[Email protected]:~$ ps1= "prompt>" prompt> Type commands here

Variables and environment variables