Steve's Shell Coding Tips

www.shellscript.sh has an entire tutorial on Shell Scripting

These tips have moved to www.shellscript.sh/tips

This is the place for small, cool, interesting or just noteworthy shell scripting tips.

They also tend to be shared with the Facebook page.

I do, less frequently, write longer articles, at http://steve-parker.org/articles.

I also have some Linux Tips, which you may find interesting.

• Controlling Loops - Controlling and Quitting Loops in Shell Scripts
• Return codes, Functions, and the number 255 - The problem with using shell functions to return integers
• Poetry in Code - The Waka Waka Poem
• Failing on Errors, whilst also Checking for Errors - An apparently contradictory position
• Pattern Substitution - editing variable values in-place
• Sorting Files by Name - including advanced sorts, and coping with spaces
• Editing a line in a text editor - Copy a command into a text editor for further editing
• The 'cp -t' command - A rant
• Efficiently Pinging a Subnet - Two methods to use the ping command to quickly scan a network
• The strstr() function in bash - Using Bash's pattern matchin to implement the well-known strstr() function.
• Giving Developers Root Access - What Could Possibly Go Wrong?!
• Search and Replace within a Variable - Editing Contents of Variables
• Calculating Hours, Minutes and Seconds - This function uses Bash's simple built-in integer mathematical capabilities to display a duration (in seconds) in a more human-readable form
• Software Development models - Explained with Cars
• The O'Reilly Animals - An Adult Coloring Book.
• rm -rf / - A Confession.
• Where There Is A Shell, There Is A Way - There Just Is.
• Christmas - Using GNU Date to work out how many days until a given event (such as Christmas, 25th December)
• Shift - A quirk of the "shift" command explained. You probably did not know this.
• The Story Of Mel - A Real Programmer.
• chmod 777 - Not needed.
• Linux Administrator - the old "What I Do / What I Think I Do" meme.
• Progress Bar - Creating a simple Progress Bar for a shell script.
• Fork Bomb! - Using shell builtin commands to deal with a fork-bombed machine.
• Sorting on Fields - Understanding the 'sort' utility.
• Simple Shell Functions - A vital step on the journey towards shell scripting proficiency.
• Expanding Lists - a useful way of expanding lists automatically. Useful for Bart Simpson, useful for you.
• Expanding Sequences - a useful way of automatically expanding lists of numbers and characters. With Bash, you don't need to type "for x in 1 2 3 4 5", or do lots of other laborious typing. It can expand all sorts of numbers, and letters, for you, in ways that you probably never knew.
• Checking the exit status of ANY command in a pipeline - normally you only get the exit status of the last command in a pipeline - this way, you can get the status of any command in a pipline of any length
• Nifty use of Grep in a Loop that you wouldn't ordinarily think of
• RPM Package Versions and how to deal with awkward version numbers
• Trap Die Tip - the smart way to deal with errors

These should accumulate over time, to become a library of the useful, the quirky and the just plain odd.

Check out the new Shell Scripting Tutorial at www.shellscript.sh

This is a full Shell Scripting Tutorial. Which you can buy at Amazon or direct from me. And there's a 600-page book.

Invest in your career. Buy my Shell Scripting Tutorial today:

 

See my other publications here: http://steve-parker.org/publications/.