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Glenn D.

01-20-2011 06:07 AM

grep query to list 1 line [which is fixed] and the next line after it [variable text]

Hello,
How can I list the following with grep.
I want to extract 2 lines fron a text file

The fixed known part if it exists will static text and the text line after it will change.

A sample file
.
.
textline1
.
.
build: extracting built packages...
somename-2.6.36.3-16.1.i586.rpm
anothername2.6.36.3-16.1.i586.rpm
.
<eof>

In the above case it would return
build: extracting built packages...
somename-2.6.36.3-16.1.i586.rpm

If the fixed part does Not exist how can I return error code 1
Thanks Glenn

syg00

01-20-2011 06:19 AM

what did your reading of the manpage indicate ?

AlucardZero

01-20-2011 06:20 AM

grep -A1 "build: extracting built packages" foofile

Code:

      -A NUM, --after-context=NUM

              Print NUM lines of trailing context after matching lines.  Places a line containing

              a group separator (--) between contiguous  groups  of  matches.  With  the  -o  or

              --only-matching option, this has no effect and a warning is given.

druuna

01-20-2011 06:21 AM

Hi,

grep -A1 "build: extracting built packages..." infile

Grep already tells you if the grep succeeded or not (echo $?)
0 - lines are found
1 - lines are not found
2 - an error occurred

Hope this helps.

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