Shell Programming and Scripting

Hi,

i was tried using the awk command for replacing '-' in the second column. but the below command replacing the entire file.

Code:

cat 1.txt |awk '{gsub(/-/,"")}1'

Input file

Code:

1,2,3,-4,5,6
1,-2,3,4,5,-6
1,2,3,4,5,6
1,-2,3,4,-5,6

Output file

Code:

1,2,3,-4,5,6
1,2,3,4,5,-6
1,2,3,4,5,6
1,2,3,4,-5,6

Hello onesuri,

Following may help you in same.

Code:

awk '{sub(/\-/,X,$2);} 1' FS=, OFS=,  Input_file

Output will be as follows.

Code:

1,2,3,-4,5,6
1,2,3,4,5,-6
1,2,3,4,5,6
1,2,3,4,-5,6

Also for your code following are the things which you could correct.
i- awk could read Input_file by itself so no need to use cat.
ii- gsub(/-/,"") means it will substitute match for all matches so to restrict it to a very first match you could use sub with only $2 as you needed to replace values in 2nd field only. Also in case we have more than 1 occurrence of - in $2 then we could use gsub(/-/,X,$2).
iii- BY default awk uses space as a field separator so here you should mention field separator either by -F"," or by FS=, so that it will make , as field separator.

Hope this helps.

Thanks,
R. Singh

Or

Code:

awk -F, '$2<0{$2=-$2}1' OFS=, file
1,2,3,-4,5,6
1,2,3,4,5,-6
1,2,3,4,5,6
1,2,3,4,-5,6

Got Perl?

Code:

perl -pe 's/^(\d+,)-/$1/' onesuri.file

Got sed?

Code:

sed 's/^\([^,]*,\)-/\1/' onesuri.file