timer.1.ronn

timer(1) -- countdown timer

SYNOPSIS

timer duration

DESCRIPTION

timer(1) is a countdown timer.

While the timer is running, the remaining time is displayed. The command exits when the time remaining reaches 0.

ARGUMENTS

The argument specifies the duration. Some examples of valid arguments follows:

5s        Five seconds
22.9s     Twenty-two and 9/10 seconds
179s      179 seconds (or two minutes and 59 seconds)
7m        Seven minutes
32m30s    32½ minutes
1h45m     One hour and 45 minutes
2h56m4s   Two hours, 56 minutes, and 4 seconds
5h        Five hours
100h      One hundred hours

EXAMPLES

Pause for 5 seconds, showing the countdown:

timer 5s

After 2 minutes and 30 seconds, play an mp3 (with the command aplay alarmbell.mp3):

timer 2m30s && aplay alarmbell.mp3

Print "hello, world" after waiting 21 minutes:

timer 21m && echo "hello, world"

EXIT VALUES

0 Normal command exit (timer reached 0)
1 Quit by user (with q key)
2 Quit by Control-C or SIGKILL
3 Error (bad arguments)

When using timer in loop in a shell script, use this code to have the script exit when the timer is interrupted, either with a q or Q keypress, or a Control-C or SIGKILL from another source:

timer 600s
# exit if interrupted
if [ $? -ne 0 ]
then
    exit 1
fi

The following causes the shell script to exit if it receives an interrupt signal (Control-C), but if the user types a q or Q, timer will quit early, and the loop inside the shell script will continue to execute:

timer 600s
# ignore user quit with q or Q key,
# but exit if interrupted with SIGKILL (Control-C)
if [ $? -eq 2 ]
then
    exit 1
fi

BUGS

The time is always shown with a 24-hour clock, even when the duration is set with a 12-hour clock.

AUTHOR

Jay Ts (http://jayts.com)

COPYRIGHT

Copyright 2019 Jay Ts

Released under the GNU Public License, version 3.0 (GPLv3) (http://www.gnu.org/licenses/gpl.html)