BASH Shell related tutorial/FAQ

Change default shell to bash on Macos Catalina

last updated October 8, 2019 in BASH Shell, Mac OS X, UNIX

I noticed that my default shell set to zsh on Macos Catalina. How do I change my default shell to bash on Macos Catalina using the command line or GUI options?

Linux run a command with a time limit (timeout)

last updated September 26, 2019 in BASH Shell, CentOS, Debian / Ubuntu, Linux, Programming, RedHat and Friends, Suse, UNIX

I want to start command called foo, and kill it if still running after given DURATION in seconds. How do I run a command a time Limit on Linux? How do I run a Linux command, and have it timeout (abort) after N seconds?

How do I force delete a directory in Linux?

last updated July 5, 2019 in BASH Shell, CentOS, Debian / Ubuntu, Linux, RedHat and Friends, Suse

I am trying to delete a directory in Linux using the rmdir dir1 command. But, I am getting an error that read as follows:
rmdir: failed to remove `dir1': Directory not empty
How do I force remove and delete a directory in Linux?

Check if a directory exists in Linux or Unix shell

last updated May 21, 2019 in BASH Shell, KSH Shell, Linux, UNIX

I need to check if a directory exists or not, within a shell script running on Linux or Unix-like system? How do I check if a directory exists in a shell script?

How to rename multiple folders in Linux using command line

last updated May 19, 2019 in BASH Shell, Linux, UNIX

I am new to Linux programming and bash shell commands. I have a folder structure as dir1, dir2, dir3 and I would like to rename it as dir001, dir002, dir003. How do you rename multiple folders in Linux?

Linux bash exit status and how to set exit status in bash

last updated March 7, 2019 in BASH Shell, CentOS, Debian / Ubuntu, FreeBSD, Linux, Suse, UNIX

Can you explain bash exit status code? How do I set bash exit status in my Linux shell scripts?

How to find Intel NUC BIOS version and model on Linux

last updated January 26, 2019 in BASH Shell, CentOS, Debian / Ubuntu, Hardware, Linux, RedHat and Friends, Suse

I installed Linux on Intel NUC. I need to find Intel NUC BIOS version. How do I find out BIOS version, date, and model name of my Intel NUC using Linux command-line options?

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