Comparing the Contents of Two Folders with `diff` using Process Substitution

Bash Tip: Comparing the Contents of Two Folders with diff using Process Substitution

One handy feature of Bash is "Process Substitution", which allows the output of a command to be treated as if it's the content of a file. This is particularly useful when you want to use the diff command to compare the contents of two directories.

Instead of comparing files, you can compare the list of files in each directory:

diff <(ls /path/to/directory1) <(ls /path/to/directory2)

Here's how it works:

  1. <(...) - This is the process substitution. Bash executes the command inside the parentheses and makes the output appear as if it's coming from a temporary file.

  2. ls /path/to/directory1 and ls /path/to/directory2 - These commands list the files in the specified directories.

  3. diff - Compares the outputs of the two ls commands, effectively showing you the differences in file presence between the two directories.

This trick allows you to quickly spot differences in file names between two directories without digging through each one manually or using more complex methods!