How can I re-use pipes?

A file full of shell commands is called a *shell script, or sometimes just a "script" for short. Scripts don't have to have names ending in .sh, but this lesson will use that convention to help you keep track of which files are scripts.

Scripts can also contain pipes. For example, if all-dates.sh contains this line:

cut -d , -f 1 seasonal/*.csv | grep -v Date | sort | uniq

then:

bash all-dates.sh > dates.out

will extract the unique dates from the seasonal data files and save them in dates.out.