regex

A little Scala `sed` class

A few times during the past year I got tired of trying to remember the Unix/Linux sed syntax while wanting to make edits to many files, so this weekend I wrote a little sed-like Scala class.

A large collection of Unix/Linux ‘grep’ command examples

Linux grep commands FAQ: Can you share some Linux/Unix grep command examples?

Sure. The name grep means "general regular expression parser", but you can think of the grep command as a "search" command for Unix and Linux systems: it's used to search for text strings and more-complicated "regular expressions" within one or more files.

I think it's easiest to learn how to use the grep command by showing examples, so let's dive right in.

A big collection of Unix/Linux ‘find’ command examples

Linux/Unix FAQ: Can you share some Linux find command examples?

Sure. The Unix/Linux find command is very powerful. It can search the entire filesystem to find files and directories according to the search criteria you specify. Besides using the find command to locate files, you can also execute other Linux commands (grep, mv, rm, etc.) on the files and directories you find, which makes find extremely powerful. 

Scala: How to extract parts of a String that match regex patterns

This is an excerpt from the Scala Cookbook (partially modified for the internet). This is Recipe 1.9, “Extracting Parts of a String that Match Patterns.”

Problem

You want to extract one or more parts of a Scala String that match the regular-expression patterns you specify.

Solution

Define the regular-expression (regex) patterns you want to extract, placing parentheses around them so you can extract them as “regular-expression groups.” First, define the desired pattern:

How to find regex patterns in Scala strings alvin July 9, 2017 - 7:11pm

This is an excerpt from the Scala Cookbook (partially modified for the internet). This is Recipe 1.7, “Finding Patterns in Scala Strings.”

Problem

You need to determine whether a Scala String contains a regular expression pattern.

How to search multiple jar files for a string or pattern (shell script)

Here’s a Unix shell script that I use to search Java Jar files for any type of string pattern. You can use it to search for the name of a class, the name of a package, or any other string/pattern that will show up if you manually ran jar tvf on each jar file. The advantage of this script — if you’re a Unix, Linux, or Cygwin user — is that it will search through all jar files in the current directory:

How to replace newline character with sed on Mac OS X (macOS)

I don’t have much time to explain this today, but ... if you want to see how to use the sed command on a Mac OS X (macOS) system to search for newline characters in the input pattern and replace them with something else in the replacement pattern, this example might point you in the right direction.