Small scripts for repetitive tasks

One thing that I like to do is write a script for seemingly trivial things that I do more than once. I do this as it turns out that I end up needing them again.

One example is a pair of script I use when testing rst2pdf. rst2pdf’s tests work by creating a PDF and then comparing this to a reference PDF. If they are different, then the test has failed. When a test fails, I need open up the PDF created by the test that’s in tests/output/{test-name}.pdf and also the reference pdf in tests/reference/{test-name}.pdf. This isn’t difficult, it’s just this command line:

$ open "tests/output/test-name.pdf" && open "tests/reference/test-name.pdf"

I use the && operator as sometimes a test fails and doesn’t create a PDF. I usually don’t immediately notice this and do not need to see the reference PDF when this situation occurs.

Not difficult to write and history makes it easy enough to find a previous command and edit appropriately.

However, it’s tedious enough to edit a command line, that I just wrote a script:

~/bin/openpdfs:

#!/usr/bin/env bash

# open the rst2pdf test result PDF and the reference one

open "tests/output/$1" && open "tests/reference/$1"

Took 5 minutes and I made working on rst2pdf that much easier as I can now just do:

$ openpdfs test-name.pdf

While using it, I soon discovered that when copying the name of the failed test, I sometimes didn’t copy the .pdf extension when double clicking, so I tweaked:

#!/usr/bin/env bash

# open the rst2pdf test result PDF and the reference one

basename=$(basename "$1")
name=$(echo "$basename" | cut -f 1 -d '.')

open "tests/output/$name.pdf" && open "tests/reference/$name.pdf"

This little addition meant that I could be more lax with the copy from the command line output, which again makes working with the script that much easier and more pleasant.

I also noticed that sometimes I’d fail to paste and would run openpdfs without any argument, so I added some help info:

#!/usr/bin/env bash

# open the rst2pdf test result PDF and the reference one

if [ -z "$1" ] ; then
    echo "$(basename $0): open rst2pdf test and reference PDF"
    echo "Usage: $(basename $0) "
    exit 1
fi

basename=$(basename "$1")
name=$(echo "$basename" | cut -f 1 -d '.')

open "tests/output/$name.pdf" && open "tests/reference/$name.pdf"

Over the course of a few months, this script has gone from a one-liner to a more flexible solution as I’ve seen its value.

I cannot recommend enough this approach enough to command you find yourself running frequently. It makes those tasks easier and more enjoyable.