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Your favorite command and mine - grep

 
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# 1  
Old 01-06-2006
Your favorite command and mine - grep
Is their a way to grep for only one occurrence? Here is an example:

given the file information:

BCX 3 5
BCX 23 94
BNG 34 34
BCX 2 09

if I do:

Code:
grep BCX ./file

then i get them all, how can i get just one of them. But let's say there could be a variable number of the desired string. Thanks in advance.
# 2  
Old 01-06-2006
Do you only want to test the presence of BCX in the file ?

You can do the following

Code:
grep -q 'BCX' file && echo "BCX found" || echo "No BCX found"

If you need only one occurence, then

Code:
grep -m 1 'BCX' file

-m and -q are available on GNU grep.
# 3  
Old 01-06-2006
based on which occurence you need,

Code:
grep BCX file | awk 'if NR == <occurence_no_needed> {print }'

Code:
grep BCX file | head -1

Is the above your requirement ?
# 4  
Old 01-06-2006
Code:
$ cat wxornot
BCX 3 5
BCX 23 94
BNG 34 34
BCX 2 09
$ while read line; do
>   echo "${line}" | grep BCX && break
> done < wxornot
BCX 3 5

If you want to assign a value to a variable, then
$ FOO="BCX"
then change the grep to
... | grep "${FOO}" && break

Cheers
ZB
# 5  
Old 01-06-2006
How about:
sed -n '/BCX/ {p;q;}' < data
# 6  
Old 01-07-2006
Quote:
Originally Posted by Perderabo
How about:
sed -n '/BCX/ {p;q;}' < data
Perderabo,

Code:
sed -n '/BCX/ {p;q;}' < data

works very well like
Code:
sed -n '/BCX/ {p;q;}' data

Is there any difference in the above command, other than syntax ?

Vino
 
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