Shell Scripting Contd
- Scripting is a list of commands that are executed in a particular order.
-
Generally the script executes the commands in the order they are written, but we can also specify
- instructions to repeat the same command multiple times (loops)
- to skip some commands based on some conditions (conditionals)
-
Sample script
#!/bin/bash
echo 1
echo 2
echo 3
echo 4
echo 5
- Execute this script
hello.sh

- Consider the following activities
- Create a directory under /opt/backup folder that has today’s date in the name eg
/opt/backup/qtdevops-03022023
- Copy all the files from /home/qtdevops/ into this directory
- Solution:
- Find a command to get the date and then data in some format.
- Refer Here for the script added
Variables
- Variables will store the value and we can use the values further in the script
- Types of Variables:
- Environmental Variables:
- The shell maintains environmetal variables which are common to applications/scripts across the current session

- To use the environmental variable
$<ENV-VAR-NAME>
- To set environmental variables you can use export command

- User Variables:
- These are the variables set in a shell script
- Refer Here for the usage of user variables
Exercise
- Findout all the environmental and user variables in the Refer Here
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