Summary

At this point you should be able to create shell scripts to help you when you run into repetitive tasks on the command line.

Even though shell scripting languages are complete programming languages, you should also take the time to evaluate whether or not making a shell script is the right tool 🛠️ for the job:

• Shell scripts can help quickly apply a sequence of operations to files.
• Shell scripts can operate on strings, but it’s pretty painful!
• Shell scripts usually can’t do basic math (you have to use a separate calculator program, like bc).
• Shell scripting languages don’t usually or trivially allow you to build complex composite data structures and objects (no classes), so building up abstractions can be tricky (if possible at all).
• Shell scripting languages don’t usually (or ever) have the kind of supporting tools that other programming languages have (no debuggers, no libraries, no specific IDEs, no …).

Shell scripts are great for quickly finding files and running programs on those files, other programming languages are usually going to be better for actually doing stuff to the files.

Further reading

Just like programming (and anything, really), shell scripting goes way beyond what you’ve been introduced to here. You’ve got a good start, but as you keep working with shell scripting, you’ll find yourself running into situations where you need to get some more help.

• You can read the manual page for your shell to learn more about its scripting language (e.g., man bash or man tcsh).
  • Sections of interest in the manual page for bash include the CONDITIONAL EXPRESSIONS section and the Compound Commands subsection.
• Joshua Levy’s “The Art of Command Line” is a very good resource that’s been translated into many languages. It’s a good reference to keep in your bookmarks.
• ShellCheck is a tool for identifying and then helping you fix possible bugs in your shell scripts.
• The Advanced Bash-Scripting Guide is a comprehensive guide for shell scripting with Bash.