Bash sleep in milliseconds

bash timer sleep
Noqrax picture Noqrax · Aug 25, 2015 · Viewed 76.6k times · Source

I need a timer which will work with milliseconds. I tried to use sleep 0.1 command in a script, but I see this error message:

syntax error: invalid arithmetic operator (error token is ".1")

When I run sleep 0.1 in terminal it works fine.

Please help me!

EDIT: Sorry I have made a mistake:

function timer
{
while [[ 0 -ne $SECS ]]; do
    echo "$SECS.."
    sleep 0.1
    SECS=$[$SECS-0.1]
done
}

Line sleep 0.1 was 5th and SECS=$[$SECS-0.1] was 6th. I just garbled lines. The problem was in 6th line, because bash can't work with float numbers. I changed my function as below:

MS=1000
function timer
{
while [[ 0 -ne $MS ]]; do
    echo "$SECS.."
    sleep 0.1
    MS=$[$MS-100]
done
}

Answer

kenorb picture kenorb · Aug 25, 2015

Make sure you're running your script in Bash, not /bin/sh. For example:

#!/usr/bin/env bash
sleep 0.1

In other words, try to specify the shell explicitly. Then run either by: ./foo.sh or bash foo.sh.

In case, sleep is an alias or a function, try replacing sleep with \sleep.

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