Shell Programming and Scripting

Hi,

I have a file like this

Code:

AAA|Ra|Pa|/|@@|//|@/|/|
B|Pa|/|/|/|@|@|@

Here i want to search and replace single occurrence of "@" with blank.

Expected output is

Code:

AAA|Ra|Pa|/|@@|//|/|/|
B|Pa|/|/|/|||

when i use tr or sed command,it replaces all,can anyone help me to achieve this output.

Thanks

Moderator's Comments:

Code tags for code, please.

tr and sed have no concept of 'column', and trying to brute-force a regex that does can be confusing.

awk supports columns directly.

Code:

awk -F"|" -v OFS="|" '{ for(N=1; N<=NF; N++) if($N == "@") $N="" } 1' filename

Cool Command,
Needs a " were the delimiter is set.

Code:

linux:~$ awk -F"|' -v OFS="|" '{ for(N=1; N<=NF; N++) if($N == "@") $N="" } 1' filename
> 
linux:~$ awk -F"|" -v OFS="|" '{ for(N=1; N<=NF; N++) if($N == "@") $N="" } 1' filename
AAA|Ra|Pa|/|@@|//|@/|/|
B|Pa|/|/|/|||

At least on my red hat bash machine.

The output of the command does not match the expected output. awk is looking for a field that consists of nothing but a single @ instead of a field containing a single @ among other possible characters.

Before investing any time on a fix, I believe the original poster should specify what they mean by a single @. Is singularity determined by the immediately surrounding characters or by the contents of a field? For example, does a field such as ...|@\@|... consist of two singles, both of which should be replaced? Or should that field be left as it is? Similarly, in ...|@\@@|..., should the first @ be replaced or not?

Regards,
Alister

Hi

Thanks for your reply.

Here singularity is determined by contents of the field i.e. if @ occurs more then once in a field,i need to remove it otherwise leave it as it is.

You have given two contradictory explanations. It's probably best to start from the beginning, with a few lines of sample input containing as many distinct variations in field values as possible, along with the desired output.

This is probably not a complicated problem to solve, but not knowing exactly what should be done will likely result in wasted time on both sides, with us having to refine or scrap a first round of solutions, and with you having to ask for further assistance.

Regards,
Alister

Hi,

I apologies for the last post.

Correct statement is:-

Here singularity is determined by contents of the field i.e. if @ occurs only once in a field,i need to remove it otherwise leave it as it is.