Pattern matching problem

Shell Programming and Scripting
1

Hi I need a bash script that can search through a text file for all lines starting with 71502FSC1206 on every line it finds starting with this I need to place a letter F at the 127 position on that line.

Thanks

Paul

2 
cat file | grep "^71502FSC1206" | sed 's/127/F/g'
3

Thanks for the reply but that did not work, I need it to place a Letter F at the 127th position on every line it finds that starts with 71502FSC1206 :b:

4

can you post the sample input file and expected output

---------- Post updated at 08:03 PM ---------- Previous update was at 07:59 PM ----------

try this...

awk '/71502FSC1206/{$0=substr($0,1,126)"F"substr($0,128,length($0))}1' input.txt
5

To make that change with sed:

sed '/^71502FSC1206/s/.\{126\}/&F/' file

With ed:

ed -s file <<'EOED'
g/^71502FSC1206/s/.\{126\}/&F/
w
q
EOED

Regards,
Alister

6

sed:

sed '/^71502FSC1206/s/./F/127'

--
Some awks can do this:

awk '/^71502FSC1206/{$127="F"}1' FS= OFS= infile
7

Many thanks everyone! really really appreciate the help, all working now :b: