Add Reverse Each Line Of A File as a Unix TIL

README.md

@@ -10,7 +10,7 @@ working across different projects via [VisualMode](https://www.visualmode.dev/).
 
 For a steady stream of TILs, [sign up for my newsletter](https://visualmode.kit.com/newsletter).
 
-_1780 TILs and counting..._
+_1781 TILs and counting..._
 
 See some of the other learning resources I work on:
 
@@ -1796,6 +1796,7 @@ If you've learned something here, support my efforts writing daily TILs by
 - [Rename A Bunch Of Files By Constructing mv Commands](unix/rename-a-bunch-of-files-by-constructing-mv-commands.md)
 - [Repeat Yourself](unix/repeat-yourself.md)
 - [Replace Pattern Across Many Files In A Project](unix/replace-pattern-across-many-files-in-a-project.md)
+- [Reverse Each Line Of A File](unix/reverse-each-line-of-a-file.md)
 - [Run A Command Repeatedly Several Times](unix/run-a-command-repeatedly-several-times.md)
 - [Run A cURL Command Without The Progress Meter](unix/run-a-curl-command-without-the-progress-meter.md)
 - [Safely Edit The Sudoers File With Vim](unix/safely-edit-the-sudoers-file-with-vim.md)

unix/reverse-each-line-of-a-file.md

@@ -0,0 +1,64 @@
+# Reverse Each Line Of A File
+
+The [`rev` command](https://man7.org/linux/man-pages/man1/rev.1.html) can be
+used to reverse each line in a file. Every line is left where it is relative to
+other lines, but the contents of each line is reversed.
+
+So a file that contains the following text:
+
+```bash
+❯ cat stuff.md
+Three
+Two
+One
+go racecar go
+```
+
+can be piped to `rev` to get the following output:
+
+```bash
+❯ rev stuff.md
+eerhT
+owT
+enO
+og racecar og
+```
+
+This is an odd utility that doesn't have too much use that I can imagine. After
+a brief chat with Claude where I asked for some practical use cases, the one
+that stood out the most to me is to reverse a list of filenames, sort them, and
+then reverse them again (putting them back in readable order). This can shuffle
+filenames with similar endings near each other like source and test files.
+
+Here is a list of files for me [`py-vmt`
+project](https://github.com/jbranchaud/py-vmt):
+
+```bash
+❯ fd -t f .
+README.md
+pyproject.toml
+src/py_vmt/__init__.py
+src/py_vmt/cli.py
+src/py_vmt/session.py
+src/py_vmt/time_helpers.py
+tests/src/py_vmt/test_cli.py
+tests/src/py_vmt/test_session.py
+```
+
+Now I can pipe the output of that `fd` command through `rev | sort | rev` to get
+my files organized in a different way.
+
+```bash
+❯ fd -t f . | rev | sort | rev
+README.md
+pyproject.toml
+src/py_vmt/__init__.py
+tests/src/py_vmt/test_cli.py
+src/py_vmt/cli.py
+tests/src/py_vmt/test_session.py
+src/py_vmt/session.py
+src/py_vmt/time_helpers.py
+```
+
+Again the value of doing something like this is a bit tenuous. At the very least
+it is fun to know about.