script

Linux: How to get the basename from the full filename

As a quick note today, if you’re ever writing a Linux shell script and need to get the filename from a complete (canonical) directory/file path, you can use the Linux basename command like this:

$ basename /foo/bar/baz/foo.txt
foo.txt
How to write a Scala shell script that reads input from STDIN alvin October 29, 2017 - 1:52pm

As a quick note, if you need an example of how to write a Scala shell script that reads from STDIN (standard input) and writes to STDOUT (standard output), this code shows a solution:

#!/bin/sh
exec scala -savecompiled "$0" "$@"
!#

import scala.io.StdIn

var line = ""
while ({line = StdIn.readLine(); line != null}) {
    println(line)
}

How to process every line in a file with a Unix/Linux shell script

Unix/Linux shell script FAQ: How do I write a Unix or Linux shell script where I "do something" for every line in a text file?

Solution: An easy way to process every line in a text file is to use a Unix/Linux while loop in combination with the Linux cat command, like this:

Example: How to use javapackager to build a MacOS application bundle

Table of Contents1 - Building a MacOS application bundle with javapackager2 - The longer story3 - The Mac/Java class4 - The three scripts5 - javapackager notes

I recently learned how to use the Java javapackager command to build a macOS application bundle — i.e., a regular macOS application — from a Java application. In this tutorial I’ll show how to create a Mac application bundle from a simple Java class, in this case a Java Swing class.

A Linux shell script to find large files

I made a mistake in configuring logrotate on a new Linux system, and almost ran into a problem because of that. Fortunately I saw the problem before it became a BIG problem, but as a result, I decided to add a script to my Linux system to check for large files, typically log files that have grown out of control for one reason or another.

Here then is a simple Linux shell script I named LargeFileCheck.sh, which searches the filesystem for files that are larger than 1GB in size:

A Linux shell script to rename files with a counter and copy them

As a brief note today, I was recently looking for all Messages/iMessage files that are stored on my Mac, and I used this shell script to copy all of those files — many of which have the same name — into a directory named tmpdir, giving them all new names during the copy process:

count=1
for i in `cat myfiles`
do
    fname=`basename $i`
    cp $i tmpdir/${count}-${fname}
    count=`expr $count + 1`
done
How to use command line arguments in Haskell alvin August 13, 2016 - 2:30pm

As a quick note to self, this source code from the online version of Learn You a Haskell shows how to read command line arguments in Haskell: