Tom Ordonez

Data Science, Machine Learning, Growing Teams

Bash Commands for Productivity


Here are some interesting bash commands to run from the shell for productivity.

Bash Commands for Productivity

Make changes to many directories

If you want to create the same file in multiple directories.

For example. I have these directories:

$ pwd
~/languages/

$ ls
python java cpp

I wanted to create an index.rst inside each directory:

$ for i in */; do touch "$i"/index.rst; done

Now these directories have that file:

  • ~/languages/python/index.rst
  • ~/languages/java/index.rst
  • ~/languages/cpp/index.rst

I moved one level up on my directory:

$ cd ..
$ ls
languages books tools frameworks

Inside these directories I also have an index.rst such as:

  • ~/languages/index.rst
  • ~/books/index.rst
  • ~/tools/index.rst
  • ~/frameworks/index.rst

Ooops I forgot to add a title inside the index.rst for the directories inside languages:

$ for in in */; do echo "Title" >> "$i"/index.rst; done

Oh wait. I made a mistake.

I am still inside my main directory:

$ pwd
~/
$ ls
languages books tools frameworks

I only wanted to add "Title" inside index.rst for the subdirectories of languages:

  • ~/languages/python/index.rst
  • ~/languages/java/index.rst
  • ~/languages/cpp/index.rst

And NOT for the directories of home:

  • ~/languages/index.rst
  • ~/books/index.rst
  • ~/tools/index.rst
  • ~/frameworks/index.rst

If I open this: ~/languages/index.rst

Now I have my index content and the last line is Title. This sucks. How do I remove the last line of multiple files now?

Remove the last line of multiple files

Let me see where I am:

$ pwd
~/
$ ls
languages books tools frameworks

As seen here. This is a solution to remove the last line from a file:

sed -i '$ d' foo.txt

Applied to many files:

$ for i in */index.rst; do sed -i '$ d' "$i"; done

Now the last line is gone.

Let's go to the correct directory:

$ cd languages/
$ for in in */; do echo "Title" >> "$i"/index.rst; done