sleep
sleep does nothing for a given length of time, then exits.
sleep number[suffix]...
$ sleep 5 # pause for five seconds
$ sleep 1.5h # pause for an hour and a half
It is used to space things out — a pause between the steps of a script, a delay before a retry.
Specifying the duration #
number may be a whole number or a fraction. A suffix gives the unit:
| Suffix | Unit |
|---|---|
s | Seconds. This is the default if no suffix is given. |
m | Minutes. |
h | Hours. |
d | Days. |
Given more than one argument, sleep waits for the sum of them — sleep 1m 30s pauses for ninety seconds.
Exit status #
| Code | Meaning |
|---|---|
0 | The full time elapsed. |
1 | A bad argument, or sleep was interrupted before the time was up. |