As a compound command, a while loop can also accept the output of another command as input, using a pipe. For example, to pass the output of who -T to the loop as input, to print only the terminal names for active users on the system, we might write:
who -T | while read -r username state terminal _ ; do
printf '%s\n' "$terminal"
done
Get Bash Quick Start Guide now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
Get Mark Richards’s Software Architecture Patterns ebook to better understand how to design components—and how they should interact.
Dive in for free with a 10-day trial of the O’Reilly learning platform—then explore all the other resources our members count on to build skills and solve problems every day.
Start your free trial Become a member now