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How to validate unsupported Flags in Bash Script on Debian 12

To validate unsupported Flags in Bash Script on Debian 12

Introduction

Validating unsupported flags in a Bash script means checking if users are using the script with the correct flags (those little commands that start with a hyphen, like -a or -b). It's like a security checkpoint for your script, making sure it runs smoothly and doesn't get confused by wrong instructions.

Procedure

Step 1: Check the OS version by using the below command.

root@linuxhelp:~/linuxhelp# cat /etc/os-release
PRETTY_NAME="Debian GNU/Linux 12 (bookworm)"
NAME="Debian GNU/Linux"
VERSION_ID="12"
VERSION="12 (bookworm)"
VERSION_CODENAME=bookworm
ID=debian
HOME_URL="https://www.debian.org/"
SUPPORT_URL="https://www.debian.org/support"
BUG_REPORT_URL=https://bugs.debian.org/

Step 2: Create a script for unsupported flags by using the below command.

root@linuxhelp:~/linuxhelp# vim unsupportedflags

Step 3: Make the executable permission by using the below command.

root@linuxhelp:~/linuxhelp# chmod +x unsupportedflags

Step 4: Long list the files to check executable permission to the script file by using the below command.

root@linuxhelp:~/linuxhelp# ls -la
total 16
drwxr-xr-x 2 root root 4096 Dec 25 05:52 .
drwx------ 8 root root 4096 Dec 25 05:52 ..
ss-rwxr-xr-x 1 root root  560 Dec 25 05:52 unsupportedflags

Step 5: Run the script file with - flags by using the below command.

root@linuxhelp:~/linuxhelp# ./unsupportedflags -a
Script executed successfully

Step 6: Again run the script without – flags by using the below command.

root@linuxhelp:~/linuxhelp# ./unsupportedflags a
Unsupported flags are: a
Supported flags are: abc

Conclusion:

We have reached the end of this article. In this guide, we have walked you through the steps required to validate unsupported Flags in Bash Script on Debian 12. Your feedback is much welcome.

Tag : debian flags Bash-scripting
FAQ
Q
Can unsupported flags vary between different versions of Bash?
A
Yes, they can. Bash commands and their supported flags may differ between versions. Always refer to the documentation or help command specific to your Bash version.
Q
What should I do while I'm running a script, and it's complaining about unsupported flags?
A
Confirm that your script is using the correct shebang (#!/bin/bash) and that the commands within the script are compatible with the version of Bash installed on your system.
Q
Why is the "unsupported option." showing after using flags? What could be the issue?
A
Ensure that you are using the correct syntax for the flag. Some flags might require specific values or might be case-sensitive. Double-check the documentation for the exact usage.
Q
How can we find out the flags supported by a Bash command?
A
Check the manual or help documentation for the command. Use the man command followed by the command name (e.g., man ls) or use command --help to display information about supported flags and options.
Q
What does the error "unsupported option" mean in Bash?
A
This error typically occurs when a command is given an option or flag it does not recognize. It could be due to a typo, outdated software, or a feature not supported by the specific version of the command.