What are Bash special parameters is a topic I have been running away from for a while. Not anymore! I finally started getting more into bash scripting basics. Special parameters are predefined variables that Bash automatically creates. You don’t assign values to them. This was something new to me. So, after brewing a good cup …
Tag Archives: bash
10 practical Linux Text-filter examples
Hola! I put together a mini Linux text-filter examples using a data.csv file. I have copy/paste it below for your reference.I’m going to use commands like cut, grep, awk, sort, uniq, head, tail, and wc.I’ll explain each example and you can run them on your Linux command line. But first, I needed to grab a …
Work on the Linux command line fundamentals
The work on the Linux command line topic is fundamental to your day-to-day work as a Linux administrator. Below is a breakdown of each area and command, with simple explanations and practical command-line examples you can try. But, first I need to brew coffee at home – Very important! Use single shell commands and one-line …
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Linux SysVinit (runlevels) and systemd (targets) commands
Reviewing the differences between Linux SysVinit (runlevels) and Systemd (targets) commands was something I was always curious to learn. After taking a walk in New York City during the summer I decided to put this list together. How to see the current runlevel in Linux? SysVinit (older systems) Default runlevel is set in: /etc/inittabExample line: …
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Linux bootloader(GRUB) common commands
This is a topic that I haven’t reviewed much or probably nothing at all. When your Linux system boots, GRUB loads the Linux kernel and passes its options. These kernel options can help us: When to use bootloader GRUB command at boot time? You can pass kernel command parameters to GRUB at boot time or …
Print the email addresses with status=”bounced” in postfix mail log
To print the email addresses with status “bounced” only from the provided log file, you can use grep to filter lines containing “status=bounced” and then use awk to extract the email addresses. Here’s how you can do it: Explanation: This series of commands will extract and print only the email addresses from lines with status …
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4 ways to run Linux Commands in the Background
This is also another Linux command I tend to forget. I usually need to re-search how to run Linux commands in the background. This happens when I stop using the command line for a while. This time I’m going to write a brief Linux tutorial about this. First I need have brew a good cup …
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Create Symbolic Links in Linux
Symbolic links in Linux is the same as creating a shortcut in Windows. Use the ln command to create symbolic links. I was a little confusing to me when I was learning about it. But, then I got it. After a walk in the new Long Island RR station at the Grand Central Terminal in …
How to Fix Cron “Operation not permitted” error in macOS
I have been working on putting together a simple bash script to backup my client’s macOS users files to a local NAS in their office. I put this script in a cron job in my macOS Big Sur, but kept getting Operation not permitted” error in my macOS Big Sur machine. WTF! Crazy thing was …
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Install Shell Completion for Docker in macOS Big Sur
Docker Desktop comes with scripts to enable completion for the docker and docker-compose commands. The completion scripts may be found inside Docker.app, in the Contents/Resources/etc/ directory and can be installed both in Bash and Zsh. Bash Bash has built-in support for completion To activate completion for Docker commands, these files need to be copied or …
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