{"id":180,"date":"2022-11-01T22:45:39","date_gmt":"2022-11-02T02:45:39","guid":{"rendered":"https:\/\/ibis.uplinklounge.com\/?p=180"},"modified":"2022-11-01T22:45:41","modified_gmt":"2022-11-02T02:45:41","slug":"grep-sed-awk-3-magic-words","status":"publish","type":"post","link":"https:\/\/ibis.uplinklounge.com\/index.php\/2022\/11\/01\/grep-sed-awk-3-magic-words\/","title":{"rendered":"Grep, sed awk – 3 magic words"},"content":{"rendered":"\n

Today a coworker oversaw me at a terminal and commented that sometimes he feels like he’s Bilbo and I’m Gandalf. I’ll take the compliment! It’s not the first time I’ve heard something like that, and I think it’s because of my familiarity with basic system tools younger developers aren’t familiar with. I intend for this to be a crash course on pragmatic uses of three such tools: grep, sed, and awk.<\/p>\n\n\n\n

Grep, sed, and awk are all command line tools for processing text in different ways. Broadly speaking, grep searches text for patterns, sed is kind of like “find and replace” on meth, and awk is grep all grown up, back from the war with scars that tell stories. In this article we’re just going to cover the most basic, pragmatic use of these tools without taking a deep dive. My goal is exposing these wonderful, cursed tools to seekers on the path to *nix nirvana.<\/p>\n\n\n\n

What is a grep and what’s it do?<\/h2>\n\n\n\n

grep simply searches through a bunch of text for a particular word or pattern. A common use of it might be something like this:<\/p>\n\n\n\n

ls -lha | grep php<\/code><\/pre>\n\n\n\n
In this example, we’re piping the output of ls -lha (which lists files in the directory) to grep, and telling grep to search for lines that contain “php”. In other words, this would just show all files containing “php” somewhere in the file name.<\/p>\n\n\n\n
 grep \"Failed password\" \/var\/log\/auth.log | grep \"Oct 26\"<\/code><\/pre>\n\n\n\n
The above example would search \/var\/log\/auth.log for any lines containing the string “Failed password”, and output them. Except, we pipe the output to grep again with “Oct 26”, so we’ll just get a list of lines that contain both “Failed password” and <\/em> “Oct 26”.<\/p>\n\n\n\n
There’s a lot more we can cover about grep, but like I said, this is only meant to expose seekers to these tools. We’re not going to cover everything else grep can do just yet.<\/p>\n\n\n\n
Sed what now?<\/h2>\n\n\n\n
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