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Display the output of a command from the first line until the first instance of a regular expression.

Terminal - Display the output of a command from the first line until the first instance of a regular expression.
<your command here> | perl -n -e 'print "$_" if 1 ... /<regex>/;'
2009-12-22 14:06:41
User: SuperFly
Functions: command perl
1
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Display the output of a command from the first line until the first instance of a regular expression.

This command line will display the output of , from the first line of output, until the first time it sees a pattern matching .

You could specify the regex pattern /^$/ to look for the first blank line,

or /^foobar/ to look for the first line that starts with the word foobar.

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Alternatives

There are 3 alternatives - vote for the best!

Terminal - Alternatives
command | sed -n '1,/regex/p'
2009-12-22 15:04:38
User: putnamhill
Functions: command sed
Tags: sed
7
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Display the output of a command from the first line until the first instance of a regular expression.

If BREs can be used, this sed version will also get the job done.

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command | sed '/regex/q'
2009-12-29 14:52:41
User: taliver
Functions: command sed
Tags: sed
1
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Display the output of a command from the first line until the first instance of a regular expression.

Slightly simpler version of previous sed command that does the same thing. In this case, the output will stop at the command, and the entire command will be terminated as well, instead of proceeding through the whole file.

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<command> | perl -pe '/<regex/ && exit;'
2009-12-22 15:05:49
User: intuited
Functions: perl
0
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Down
Display the output of a command from the first line until the first instance of a regular expression.

Doesn't display the matching line. If you want that behaviour, you need to add "print && " before the 'exit'.

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Know a better way?

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What others think

Now I see the purpose of the question...

Comment by unixhome 37 weeks and 2 days ago

Your point of view

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