UNIX for Dummies Questions & Answers

Gurus,
I am relatively new to Unix scripting and am struck with a problem in my script. I have positional input file which has a FLAG indicator in at position 11 in every record of the file.

If the Flag has value =Y, then the record from the input needs to be written to a new file.However if the FLAG has value ="N" the record needs to be ignored

Below is the logic, sample input and expected output that i am trying to unsuccessfully implement. Any help/pointers to resolve my issue will be greatly appreciated

Regards,
Gsam

Code:

filename=$1

while read mline; do
    C_Offadd=`awk '{val=substr($mline,11,1);print val}'`
    if [ "${C_Offadd}" -eq "Y" ]; then
      echo $mline >> $filename.rew
    fi
done<$filename

Sample Input
DTLDETAIL1YAPPLE
DTLDETAIL2YBALL
DTLDETAIL3NCAT
DTLDETAIL4NDOG
DTLDETAIL5YFISH

Expected Output
DTLDETAIL1YAPPLE
DTLDETAIL2YBALL
DTLDETAIL5YFISH

No need for a while loop to read line by line. You can achieve this by using below awk code:

Code:

awk 'substr($0,11,1)=="Y"' input > output

Code:

$ cat sample31.txt
DTLDETAIL1YAPPLE
DTLDETAIL2YBALL
DTLDETAIL3NCAT
DTLDETAIL4NDOG
DTLDETAIL5YFISH

$ awk '{if (substr($0,11,1)=="Y") print $0}' <sample31.txt
DTLDETAIL1YAPPLE
DTLDETAIL2YBALL
DTLDETAIL5YFISH

Thanks Yoda & joeyg it worked like a charm ! You guys were fast & awesome !

Best Regards,
Gsam