Hello everyone,
Am writin a script with awk aiming to substitute a message in selected lines
i dont know how to insert sed command in the if condition to replace only the selected lines

awk /^VDD/'{

getline;getline;v=split($2,tab,"1V8_2V5_3V3") ;

if ($1=="|" && v!=1) {getline;getline; sed 's/ERROR/warning/g' file> tmp }


}' file

sed is not an awk built-in function; it's a separate utility. Try using sub().

Thank U for repliyin
I've tried to use sub() but it doesent work
i tried this
awk /^VDD/'{

getline;getline;v=split($2,tab,"1V8") ;

if ($1=="|" && v!=1)
{
getline;getline; str=$0;
sub (/ERROR/,"Warning",str); print str
}
}'

(I want to use sub to make a modification only in the selected line)

Have you tried reading the awk manual? There are some examples showing how to properly use the sub() function.

Thank U i have used the gsub in a gawk command and its OK
but now I am trying to save the modif of selected lines in the source file not in a new file (I've tried to use print "$0" >> filename but it puts the new lines in the end of the file)
gawk /^VDD/'{

getline;getline;v=split($2,tab,"1V8_") ;if ($1=="|" && v!=1)

{
getline;getline;str=$0;gsub(/ERROR/,"warning",str) ;
print str >> "checkSupply"
}
}'

You cannot do it with awk. You'll have to write to a new file, then rename. If you think you need to edit the file in place you should use something like ed or vi.

Rather than giving us your code, why not just give a quick description of what you want and a few lines of test data and what you would expect as output. It sounds like something than can be done by sed alone but I can't work out what you're trying to do by looking at your code.

In fact I have a file which contains ERROR messages.Some of these messages are wrong So I must select these wrong messages and make a modif only on these lines. Now with my code I can select the lines but I cant make the modif on the source file . The file must stay the same Only selected lines have to be modified

Problem solved
Thank U 4 all

You would run something like the following. Seeing as you don't want to give a proper example I've made up my own text. You'll need a sed command for each message you want to change. I'll assume you know about the pipe character | etc.

Mike

Thanks for the idea I'll try to use it maybe to improve my code