BASH Shell related tutorial/FAQ

How to return pid of a last command in Linux / Unix

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

I need to find and return the PID of the last command executed in Linux. How do I return the PID of command in Linux?

Bash get filename from given path on Linux or Unix

last updated November 14, 2019 in BASH Shell, Linux, Mac OS X, UNIX

How do I extract filename and extension in the Bash shell script from the given path? How can I get filename from the path under the bash shell?

How to find a website’s DNS (name server) address

last updated November 3, 2019 in BASH Shell, Linux, UNIX, Windows

How can I find a website’s DNS address? How do I check the current DNS servers of a domain or website using a Linux or macOS command line option? How do I find DNS address of a website using bash?

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?

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