From: TJ Luoma <luomat@gmail.com>
To: Zsh-Users List <zsh-users@zsh.org>
Subject: only run if X seconds have elapsed (time differences in seconds)
Date: Sat, 29 Dec 2012 14:40:11 -0500 [thread overview]
Message-ID: <CADjGqHtgatYEHyus2ru8vUPUJJQH48nGNVH8XbvV11nr0HhpGg@mail.gmail.com> (raw)
I very often find myself wanting to say "Run this command, but only if
it has not been run in the past X seconds.
For example, if I wanted to run something no more often than once per
day, I'd do something like this:
#!/bin/zsh
# load this so I can use EPOCHSECONDS
zmodload zsh/datetime
# this is a minimum of how many seconds should elapse between runs
RUN_EVERY=86400
# this is a text file where the previous timestamp is saved
LASTRUN=$HOME/.lastrun
# if there is no LASTRUN file, make it zero
[[ -e "$LASTRUN" ]] || echo -n 0 > "$LASTRUN"
# save current time
NOW=$EPOCHSECONDS
# get previous time, and strip out anything that is not a digit
THEN=$(tr -dc '[0-9]' < "$LASTRUN" )
# get the difference in seconds between NOW and THEN (the last time it was run
DIFF=$(($NOW - $THEN))
# if the difference is less than RUN_EVERY then exit
[[ "$DIFF" -le "$RUN_EVERY" ]] && exit 0
# if we get here, it's time to run again, so let's update LASTRUN:
echo -n "$NOW" > $LASTRUN
# And then I do whatever else the script is supposed to do here
My question is:
Is there an easier / better way to do this than the way that I am
doing it? If so, what would you recommend?
Thanks!
TjL
next reply other threads:[~2012-12-29 20:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-29 19:40 TJ Luoma [this message]
2012-12-29 23:34 ` Bart Schaefer
2012-12-30 1:00 ` TJ Luoma
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