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grepping a part of filenames

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# 1  
Old 10-18-2006
grepping a part of filenames
Hi ,

I have a list of files in a directory and filename format is as follows:
PQ223390
PQ876912
PQ768901
PQ398140 and so on

I want to grep the first four digits of all the files after PQ, into a file.
Ex:
2233
8769
6890
3981 and so on

Can anyone tell me the command?

thankx jazz
# 2  
Old 10-18-2006
Why do you need a grep to do that? You just need to parse the filenames, right ?

Code:
sed -e "s/^..\(....\).*/\1/g"

# 3  
Old 10-18-2006
Another way, ksh builtin:
Code:
while read line; do
echo ${line:2:4}
done < inputfile

# 4  
Old 10-18-2006
Thank You ALL
# 5  
Old 10-18-2006
Quote:
Originally Posted by shereenmotor
Another way, ksh builtin:
Code:
while read line; do
echo ${line:2:4}
done < inputfile

ksh builtin? Did you mean sh builtin?

Code:
[/tmp]$ cat try.ksh
#! /bin/ksh

for line in PQ223390 PQ876912 PQ768901
do
echo ${line:2:4}
done 
[/tmp]$ ./try.ksh 
./try.ksh[6]: : bad substitution
[/tmp]$

# 6  
Old 10-18-2006
Its a ksh builtin. See this what I get:
Code:
#! /bin/ksh

for line in PQ223390 PQ876912 PQ768901
do
echo ${line:2:4}
done

Output:
Code:
$./tmp
2233
8769
7689

Interactive output:
Code:
$echo $0
-ksh
$a=PQ223310
$b=${a:2:4}
$echo $b
2233

If try to run it with sh then I get same error of bad substitution which you are getting:
Code:
$cat tmp
#! /bin/sh

for line in PQ223390 PQ876912 PQ768901
do
echo ${line:2:4}
done
$./tmp
UX:sh (./tmp): ERROR: Bad substitution

I think you need to check path of your ksh if its really /bin/ksh or not. Otherwise, I'm not sure why you get bad substitution error.

Regards,
Tayyab
# 7  
Old 10-18-2006
Interesting. The man pages for ksh dont mention anything of that construct. But yes, the bash man page does.
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