Chaining Two Commands

Now that you understand what a pipe does, let's see how to use it effectively with two commands. The key is choosing commands that work well together — where the output of the first makes sense as input for the second.

A common pairing is ls with wc -l to count files:

ls | wc -l

The ls command lists files (one per line), and wc -l counts those lines. The result is the number of files in the current directory.

Another useful combination is cat with head to preview a file:

cat longfile.txt | head -5

This displays only the first 5 lines of the file. You could also use head -5 longfile.txt directly, but piping becomes essential when the first command generates output that isn't simply reading a file.

For example, combining ls -l with head:

ls -l | head -3

This shows detailed information for just the first few items in a directory. The pipe transforms two simple commands into a more powerful operation.