BASH Shell HowTo - Linux / Unix Q & A from nixCraft

Bash shell find out if a variable has NULL value OR not

last updated December 27, 2018 in BASH Shell, FreeBSD, Korn Shell Scripting, KSH Shell, Linux, UNIX

I am a new to shell scripting. How do I check for NULL value in a Linux or Unix shell scripts?

How to add bash auto completion in RHEL 8 (Red Hat Linux)

last updated November 21, 2018 in BASH Shell, Linux, RedHat and Friends

I set up a new RHEL 8 VM from cloud images, but my auto-completion of bash shell commands are not working. How do I enable autocomplete feature in RHEL 8 (Red Hat Enterprise Linux 8)? How do I write simple bash completion code in RHEL 8?

How to add bash auto completion in Ubuntu Linux

last updated February 25, 2019 in BASH Shell, Linux, Package Management, Ubuntu Linux

I set up a new Ubuntu Linux LXD container, but my auto-completion of bash shell commands are not working. How do I enable autocomplete feature in Ubuntu Linux 18.04 LTS?

Bash Shell Find Out If a Variable Is Empty Or Not

last updated August 9, 2018 in BASH Shell, CentOS, Debian / Ubuntu, FreeBSD, Linux, Suse, UNIX

My shell script depends upon user input. How do I find out if a variable called $_JAIL path is empty under a Linux / Apple OS X / Unix like operating systems? Can you tell me command on bash shell to find out if a variable is empty?

Bash Shell Script To Test For Empty Folder

last updated July 6, 2012 in BASH Shell

How do I check if a directory contains files? How do I find out if a directory contains files using bash shell under Linux or Unix like operating systems?

Linux / Unix: Find Hidden Directories, Files and Folders

last updated June 26, 2012 in UNIX

I‘m a new Unix user and trying to find the hidden directory called .movies but I do not know where it is on the file system. How do I find a hidden folder or directories under Unix like operating systems?

Unix / Linux Shell: Parse Text CVS File Separator By Field

last updated March 4, 2014 in BASH Shell, Linux, UNIX

I work for a small ISP (Internet Service Provider) and we are using Linux and Unix-like operating system with bash shell. I want to write a shell script to parse the csv file line by line. Then line must be parse again field by field. The sample input file is as follows:

example.com,username,groupname,homedir,md5password,permission,secondarygroup

I need to extract each of these example.com,username,groupname,homedir,md5password,permission,secondarygroup fields and passed to the different system utilities. How do I write a shell script to automate this task and use the bash shell to parse a text file?