how to output unique line from a file/input

[Xiaoming Zhang]

I used grep to get lines matching to a regular expression. I also like to filter the grep's output to get unique lines. How may I do it?

Thanks. Xiaoming

[Curtis Larson · Accepted solution]

you can use sort -u or uniq

[MARTINACHE]

Hi,

grep your_pattern your_file | sort -u

Regards,

Patrice.

[Paula J Frazer-Campbell]

Hi
Your can pipe your grep output ro grep again,

cat |grep |grep |etc

Build it up stage by stage to get what you require.

HTH

Paula

[Dan Hetzel]

Hi Xiaoming,

As 'uniq' looks for adjacent lines, the file needs to be sorted before.
For that reason, it's better to use 'sort -u' instead.

grep "pattern" from_file | sort -u > to_file

Best regards,

Dan

[Bill McNAMARA_1]

I know it's old, I was searching for something else and this showed up..

one of the best ways to do this is the uniq command.
| sort | uniq -c in particular may be what's needed here.

Later,
Bill