How to scan Terminal output for a string?

Question

I want to search Terminal output from a command for a string and display only the lines that include that string.

How can I do it?

I'm interested in searching the Terminal output, not a file. I have tried

ls --help | grep '--l '

but that gave me error.

Is the output in STDOUT, or already redirected to a file? Or are you asking how to redirect output to a file? — user535733, Nov 23 '19 at 19:35
@user535733: Output is in STDOUT and I want to stay it that way. I want to "filter" only certain lines. — BlueSkies, Nov 23 '19 at 20:10
@ManasSingh: The question is about filtering output of a command, not a file. — BlueSkies, Nov 23 '19 at 21:02
Related: How to use grep to search through the --help output? — steeldriver, Nov 23 '19 at 22:31

score 2 · Accepted Answer · edited Nov 24 '19 at 00:11

2

command-name | grep 'STRING'

If STRING starts with '-' or '--', it's necessary to utilize one of the following formats:

command-name | grep \\'STRING'
command-name | grep -e 'STRING'
command-name | grep -- 'STRING'

edited Nov 24 '19 at 00:11

glenn jackman

answered Nov 23 '19 at 20:39

BlueSkies

2

... or use -e 'STRING' to make it explicit that STRING is a pattern not an option; or use -- to signal end of options – steeldriver Nov 23 '19 at 22:28
1

Being more explicit about the last suggestion: grep -- --l – glenn jackman Nov 23 '19 at 22:34
1

@BlueSkies you can do it, click edit at share edit flag below your answer. – Hannu Nov 23 '19 at 23:10
2

They provided the comments so that you could edit and create a complete answer. – Hannu Nov 23 '19 at 23:12

1 Answers1