UNIX for Advanced & Expert Users

When searching for "text" in a file,
I would like to see the line containing "text"
and the line preceeding
and the line after
So I would like a 3 line output for each line matched by grep
Is there a quick way to accomplish this?
Example--

FILE.DAT contains

abcdef
123456789
xyz
hijklmnop
987654321

I would like the search for "xyz" to yield results such as:

FILE.DAT:2: 123456789
FILE.DAT:3: xyz
FILE.DAT:4: hijklmnop

Any suggestions?

A Tagore
atagore2@juno.com

from gnu grep man page:

Code:

       -A NUM, --after-context=NUM
	      Print NUM	 lines	of  trailing  context  after  matching	lines.
	      Places  a	 line  containing  --  between	contiguous  groups  of
	      matches.

       -B NUM, --before-context=NUM
	      Print  NUM  lines	 of  leading  context  before  matching lines.
	      Places  a	 line  containing  --  between	contiguous  groups  of
	      matches.

I don't have GNU grep so I can't test it. But, I think this is what you are looking for.

This is not completely correct and I can not fully debug it at this time, but it may help. Save the following as, say, /tmp/3linegrep.sed

Code:

/pattern/ {
    =
    H
    g
    n
    p
}
x
d

Given your input file and a pattern of xyz:

Code:

# sed -f /tmp/3linegrep.sed FILE.DAT
3
123456789
xyz
hijklmnop

This will display the pattern-matching line number followed by the previous line, the matched line, and the next line. There are special case issues -- last line with pattern, two successive lines with same pattern -- that I suspect do NOT work properly. It is quick and dirty.

I apologize if it is more confusing than helpful.

Hello,

You can this small script , may be it helps:

grep -n -v "0" inputfile > a1
var1=`grep "xyz" a1 |cut -d":" -f1`
var2=`expr $var1 + 1`
var3=`expr $var1 - 1`
grep "^$var3:" a1 > out
grep "^$var1:" a1 >> out
grep "^$var2:" a1 >> out


thanks

Aparna

Hey as per my knowledge you can try the cgrep command. In this command 1,1 represent matching line before and after. At the bottom of this reply i have added the usage of this command.

Command : cgrep -1,1 "xyz" FILE.DAT

Output :

123456789
xyz
hijklmnop

Usage of cgrep command :

Usage: cgrep [-pre[,post]] [-p] [-v] [-c] [-h] [-n] [-d string]
[-e] pattern [file...]

cgrep is a context grep. It displays more than the one matching line for
every match (2 before and 2 after as default).

-3 means display 3 lines before and 3 lines after the match (e.g.)
-5,12 means display 5 lines before the match and 12 lines after (e.g.)
-p means display only as much of the context as belongs to the
current paragraph. (paragraphs bounded by empty lines)
-v means invert search (display nomatches)
-c means display number of matching lines at the end of run
-h means toggle display filename before every line
-i means ignore case when matching the regexp
-n means display line number before every line
-d string means use string as the output delimiter string
-- (or -e) means end options (i.e. now comes the pattern,
for patterns starting with - )
pattern is a Perl regular expression (you better quote it !)

Please let me know if this works fine.

Thank you everyone for your suggestions.

I am on SUN-OS box
I do not have the GNU grep
I do not have the cgrep
I can utilize the other suggestions...

Thanks once more...

A Tagore