Shell Programming and Scripting

@ahamed:Can u please explain me the concept behind your methodology as i am new to shell script

---------- Post updated at 12:21 PM ---------- Previous update was at 12:10 PM ----------

Hi,
Please explain me the concept behind this as i am new to shell script

Code:

sed -e 's/|G|/:|/g' -e 's/||/|/g' input_file > new_file

s/search/replace/globally

's/|G|/:|/g' search for |G| and replace with :| wherever you find it

's/||/|/g' search for || and replace with | wherever you find it

> new_file write into new file

Actually this command alone will do the job

Code:

sed 's/|G|/:|/g' input_file > new_file

Hope this helps.

--ahamed

But if "G" is the first or last field?

I think vgersh99 had all the bases covered. It just looks a bit more intimidated with "#" as separators.

Code:

sed 's/^G|/:|/;s/|G|/|:|/g;s/|G$/|:/'

Thanks for all your help!!But i came to know that data in the file can come as 12345|1|1111|131|678|134121|1|A|BCDEF

Now i want to replace "1" which is highlighted above with "2" then how it can be done??The final output must look like:
12345|1|1111|131|678|134121|2|A|BCDEF

One more thing though "1" can come at any index, this is sure that at 7th index "1" will definetly come and i want to replace this "1" which is present at 7th index with "2"..I tried the following:
sed 's/`cut -d"|" -f7`/"2"/g' but the problem is cut command will extract "1" from 7th index and then sed command is replacing all 1's in a file with 2's
Please help

You want to change the second occurence of |1| to |2| right?
You can't keep on changing the requirements. You will first need to find a pattern.

val = which value you want to replace
newval = value to be replaced with
need = which occurence

Code:

awk -F"|" -v val="1" -v newval=2 -v need=2 '{ for(i=1;i<=NF;i++){if($i==val){ocur++; if(ocur==need){$i=newval}} v=v"|"$i }}
 END{sub(/^\|/,"",v);print v}' input_file

--ahamed

@ahamed:Appreciate your help and sorry about changing the requirements every now and then. Your solution seems to be perfect just that it is not fixed that always i want to replace 2nd occurrence of "1" to "2". The pattern in the file can be like this also:
1|1|1|2|11123|2|1|4|5|6
3333|456|1|345|1111|1|1|6|45|
1234|4|11|1|1|345|1|4|5
So it is not fixed that second occurrence of "1" is to be replaced,thing which is fixed is "1" present at 7th index is to be replaced.

so it looks like you want replace the last occurrence?

--ahamed