mirror of
https://github.com/koalaman/shellcheck.git
synced 2025-03-12 12:35:25 -07:00
Created SC2176 (markdown)
parent
d178d300f5
commit
3a0383210c
30
SC2176.md
Normal file
30
SC2176.md
Normal file
@ -0,0 +1,30 @@
|
||||
## 'time' is undefined for pipelines. time single stage or bash -c instead.
|
||||
|
||||
### Problematic code:
|
||||
|
||||
```sh
|
||||
time foo | bar```
|
||||
|
||||
### Correct code:
|
||||
|
||||
To time the most relevant stage:
|
||||
|
||||
```sh
|
||||
foo | { time bar; }
|
||||
```
|
||||
|
||||
To time everything in a pipeline:
|
||||
|
||||
```sh
|
||||
time bash -c 'foo | bar'
|
||||
```
|
||||
|
||||
Note that you can not `time sh -c` to time an entire pipeline, because POSIX does not guarantee that anything other than the last stage is waited on and therefore be recursively counted in the `times()` call that `time` depends on.
|
||||
|
||||
### Rationale:
|
||||
|
||||
This behavior is explicitly left undefined [in POSIX](http://pubs.opengroup.org/onlinepubs/9699919799/utilities/time.html).
|
||||
|
||||
### Exceptions:
|
||||
|
||||
None. This method is not given in `ksh` or `bash` where `time` is defined for pipelines.
|
Loading…
x
Reference in New Issue
Block a user