using sed to alter the third field only 2

[mfearnuk]

Hi,

How can you subsitute only one field with sed - I don't want to replace all occurrences of a string?

Regards

Martin

 

[Krunek]

Hello, Martin!

Sed doesn't recognize fields inside input line, I think. But awk does.

For example, if you want to replace the contens of the third field in input line with its logarithm, you can use this awk command:

awk '{ $3 = log($3); print }' inputfile > outputfile

I hope this helps.

Bye!

KP.

 

[mfearnuk]

Thanks,

However I have lost my field seperator in the outputfile

awk -FS\| awk '{ $3 = "00000000" print }' inputfile > outputfile


Inputfile
00001007|00719CC0|00000008|00000000|00000000|03036732

outputfile
00001007 00719CC0 00000000 00000000 00000000 03036732



Martin

 

[grega]

Martin ... this should do the trick. You need to set the Output Field Separator (OFS) as well.

awk 'BEGIN {FS="|";OFS="|"} {$3="00000000";print}' inputfile > outputfile

Greg.

 

[Guest_imported]

thanks, Greg! Examples worked great. One thing, if you're doing numeric manipulations on a string that's not a number, awk tends to add extra fields. One way I got around this is specifying the input FS in the command line,

awk -F '|' {OFS="|"}{etc...}