| 1 |
On 08.05.2009 17:10, Alan McKinnon wrote: |
| 2 |
>>> if echo hello|grep --color=auto l >/dev/null 2>&1; then |
| 3 |
>>> export GREP_OPTIONS='--color=auto' GREP_COLOR='1;32' |
| 4 |
>>> fi |
| 5 |
>>> |
| 6 |
>>> to ~/.bashrc |
| 7 |
>>> |
| 8 |
>>> Why does he echo hello, please? |
| 9 |
>> Some greps (like BSD one) might not support '--color' option, so "echo |
| 10 |
>> hello|grep --color=auto l" will return error code, skipping if clause, |
| 11 |
>> and won't break grep operation by adding an unsupported option. |
| 12 |
> |
| 13 |
> except that STDERR is combined with STDOUT and sent to /dev/null so the script |
| 14 |
> will never get it, the if is always true and the entire check is redundant. |
| 15 |
> Better would be |
| 16 |
> |
| 17 |
> if echo hello|grep --color=auto l >/dev/null ; then |
| 18 |
|
| 19 |
No. We do not want any output from echo|grep. We just want the exit |
| 20 |
code so that the following export statement gets executed iff grep |
| 21 |
returns with no errors. |
| 22 |
|
| 23 |
-- |
| 24 |
Eray |
Archives