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Gumper

Member

From: U.S.A.

Registered: 2009-10-26

Posts: 132

Help extracting data from a grep command

I'm using grep to pull some data from a log file but I can't seem to be able to get exactly what I need. What I have so far is the following:

[22:00:16]   /usr/sbin/chroot                                [ Warning ]

What I need to do is to somehow only select the "/usr/sbin/chroot" part of what grep gives me and remove the "[22:00:16]" and the "[Warning]".
I've tried using "cut" and "sed" but I can't seem to figure it out.

Could someone point me in the right direction on what to use to be able to do this?

Thanks!

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Ready yourselves, ready yourselves
Let us shine the light of Jesus in the darkest night
Ready yourselves, ready yourselves
May the powers of darkness tremble as our praises rise .... Casting Crowns-Until The Whole World Hears.

lagagnon

Member

From: an Island in the Pacific...

Registered: 2009-12-10

Posts: 1,087

Website

Re: Help extracting data from a grep command

"awk" is more suited to extracting information from columnar data.
Something like:

cat mylogfile | awk '{print $1}'

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falconindy

Developer

From: New York, USA

Registered: 2009-10-22

Posts: 4,111

Website

Re: Help extracting data from a grep command

This should be safe enough:

sed 's/^\[[^]]\+\][[:blank:]]\+//;s/[[:blank:]]\+\[[^]]\+\]$//'

"awk" is more suited to extracting information from columnar data.
Something like:

cat mylogfile | awk '{print $1}'

True, but this isn't quite columnar. Also, your cat hates you right now.

Last edited by falconindy (2011-01-04 04:58:09)

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carlocci

Member

From: Padova - Italy

Registered: 2008-02-12

Posts: 368

Re: Help extracting data from a grep command

This should be safe enough:

sed 's/^\[[^]]\+\][[:blank:]]\+//;s/[[:blank:]]\+\[[^]]\+\]$//'

I detect a terrible case of seditis regexposa

awk --re-interval -F'[ \n\t]{2,}' '{print $2}' $LOGFILE

as usual, the more a regexp is general, the uglier it gets.

I think a simple

awk '{print $1}' $LOGFILE

is better.

karol

Archivist

Registered: 2009-05-06

Posts: 25,440

Re: Help extracting data from a grep command

@carlocci
I think you meant

awk '{print $2}' $LOGFILE

falconindy

Developer

From: New York, USA

Registered: 2009-10-22

Posts: 4,111

Website

Re: Help extracting data from a grep command

This should be safe enough:

sed 's/^\[[^]]\+\][[:blank:]]\+//;s/[[:blank:]]\+\[[^]]\+\]$//'

I detect a terrible case of seditis regexposa

awk --re-interval -F'[ \n\t]{2,}' '{print $2}' $LOGFILE

as usual, the more a regexp is general, the uglier it gets.

I think a simple

awk '{print $1}' $LOGFILE

is better.

I'm comfortable in my seditis. Your --re-interval looks extremely gawkish, but that's definitely a handy flag to know about. Thanks.

Last edited by falconindy (2011-01-04 13:51:09)

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Gumper

Member

From: U.S.A.

Registered: 2009-10-26

Posts: 132

Re: Help extracting data from a grep command

Thanks for the help everyone.

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Ready yourselves, ready yourselves
Let us shine the light of Jesus in the darkest night
Ready yourselves, ready yourselves
May the powers of darkness tremble as our praises rise .... Casting Crowns-Until The Whole World Hears.