Shell Script Learning 1 (Linux script Raiders)

sudo <command> < arguments> equivalent to root permission execution command

Give executable permissions to all user files: chmod a+x script.sh

Execute script:
./script.sh#./represents the current directory

Command 1:echo "Welcome to Bash"

Command 2:printf "Hello World"

Difference: printf does not carry a newline!

Example1:

#!/bin/bash

printf "%-5s%-10s%-4s\n" No Name Mark

Command 3: View environment variables when the process is running:

cat/proc/$PID/environ (PID is the ID of the process)

Command 4: Get the ID of the process

Pgrep gedit

12501 (ID of the gedit process)

You can view the environment variables for a process by using the following command:

Cat/proc/12501/environ/gdm_keyboard_layout=usgnome_keyping=1560user=slynuxhome=/home/slynux

Change command to return a list containing environment variables and corresponding variable values

Command 5:tr ' \ n ' to replace command

Attention:

Var=value is an assignment operation, var = value is an equal operation, error prone;

Example:

Var= "Value"

echo $var (output content, using $ symbol)

The latter echo ${var}

Environment variables are variables that are not defined in the current process and are inherited from the parent process;

To add a new path in path:

Export path= "$PATH:/home/user/bin"

You can also use:
Path= "$PATH:/home/user/bin"

Export PATH

Shell Script Learning 1 (Linux script Raiders)