BASH Shell – nixCraft

How to find bash shell function source code on Linux/Unix

September 22, 2017September 22, 2017in BASH Shell, Linux, UNIX last updated September 22, 2017

I am a new Linux server user. I cannot figure out how to find out the source code of a bash function named foo() which is defined. How to locate the file where a bash function is defined and how to view the source code of foo() from shell prompt itself?

How to delete files containing a character or number/digit in their filename on Linux or Unix

August 23, 2017August 24, 2017in BASH Shell, Linux, UNIX last updated August 24, 2017

I am a new Linux system user. How do I delete file containing a character ‘a’ or ‘z’ in their filename or digit such as ‘4’ or ‘2’ in their filename on Linux or Unix bash shell prompt?

How to upgrade LXD VMs powered by Ubuntu/Debian or CentOS Linux

July 11, 2017in BASH Shell, CentOS, Debian / Ubuntu, Linux, Linux Containers (LXC) last updated July 11, 2017

I run over 10+ LXD VMs powered by CentOS Linux 7 and Debian/Ubuntu Linux. How do I upgrade all VMs automatically or on demand using Ansible tool?

How to check and verify md5/sha1/sha256 checksums for Apple MacOS X when I download files

June 30, 2017June 30, 2017in BASH Shell, Mac OS X, Security, UNIX last updated June 30, 2017

Malware is becoming more and more common for macOS. I wanted to make sure file I downloaded files such as an ISO image or firmware are safe before install on my system. How do I verify md5 or sha1 or sha256 checksums for my Apple MacOS X when I download files from the Internet?

How to display countdown timer in bash shell script running on Linux/Unix

June 24, 2017June 24, 2017in BASH Shell, Linux, UNIX last updated June 24, 2017

I want to display a countdown before purging cache from CDN network. Is there an existing command to show a conuntdown from 30..1 as 30,29,28,…1 on Linux or Unix bash shell script?

How to find and delete directory recursively on Linux or Unix-like system

June 20, 2017June 22, 2017in BASH Shell, Linux, UNIX last updated June 22, 2017

I type ‘find . -type d -iname foo -delete‘ command to find the foo directories and delete them. However, I am getting an error message that read as find: cannot delete './hourly.4/data/foo': Directory not empty on Linux server. How do delete directories based on find command output on Linux or Unix-like system?

How to run cron job every minute on Linux/Unix

June 18, 2017June 18, 2017in BASH Shell, Commands, Linux, UNIX last updated June 18, 2017

I want to run a cron job that should run a specific shell script /home/jobs/sync.cache.sh every minute. How do I use crontab to execute script every minute on Linux or Unix-like system?