UNIX – 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 find disk I/O latency with ioping monitoring tool on Linux

September 21, 2017in FreeBSD, Linux, Mac OS X, OpenBSD, UNIX last updated September 21, 2017

How do I monitor disk I/O latency in real time on Linux, FreeBSD, OpenBSD, and MacOS operating system?

How to find and replace text/IP address with Ansible

September 21, 2017in Linux, UNIX last updated September 21, 2017

I need to find an IP address in the sshd_config file and replace with a fresh one for over 100+ VMs. How do I use Ansible to do so? Is it possible to search replace single string or IP address?
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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 change or configure OpenBSD package install mirror

August 16, 2017in OpenBSD, Package Management, UNIX last updated August 16, 2017

openbsd commandI am trying to install nginx server on OpenBSD but keep getting an error that read as follows when I run the pkg_add command:

https://mirror.leaseweb.com/pub/OpenBSD/6.1/packages/amd64/quirks-2.304.tgz” title=”quirks-2.304.tgz: ftp: Error retrieving file: 404 Not Found
signify: gzheader truncated
https://mirror.leaseweb.com/pub/OpenBSD/6.1/packages/amd64/nginx-1.10.2p2.tgz” title=”nginx-1.10.2p2.tgz: ftp: Error retrieving file: 404 Not Found
signify: gzheader truncated

How do I change or configure OpenBSD package install mirror for the pkg_add command?

How to test PHP 7 and WordPress MySQL/MariaDB Database connectivity using a PHP script

August 15, 2017August 15, 2017in Linux, MySQL, PHP, UNIX last updated August 15, 2017

I wanted to test if my PHP 7 and MySQL/MariaDB for WordPress are working. If not I wanted to see some error on screen or for my monitoring system. How to write a script for a quick PHP MySQL DB connection test for WordPress or any other database and send an email or text when site is down?

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?