How to replace specific row using sed or awk based with run command

With grep:

grep -oP 'sum=\K.*' inpufile > outputfile

grep with -P(perl-regexp) parameter supports \K, which use to ignoring the previously matched characters.

With awk:

awk -F"=" '{ print $NF; }' inputfile > outputfile

in awk the variable NF represent the total number of fields in a current record/line which is point to the last field number too and so $NF is its value accordingly.

With sed:

sed 's/^.*sum=//' inpufile > outputfile

^.*=sum replace all characters(.*) between starting of line(^) and last characters(sum=) with whitespace char.

Result:

-6.97168e-09
6.97168e-09
-5.12623e-12
5.12623e-12
-6.936e-09
6.97169e-09
-5.1e-12
5.12624e-12

With cut:

cut -d'=' -f2 inputfile > outputfile

if you want save same values into a same file and each separately, with awk you can do:

awk -F"=" '{print $NF >($NF); }' inputfile > outputfile

Another solution with awk using sub:

awk -F, 'sub("^[0-9]+\\s","",$3)' OFS=, file 

Output:

qw12er,foo,bn5mgh
rt8yp,foo,gh78jk
bn852mv,foo,78ghjkh
tgbr,foo,ujmyhn
wsx2d,foo,ui52ohn
tgbr,foo,ujmyhn
ikl896o,foo,wsxdc52

Explanation:

• -F,: set the comma as input field separator

• OFS=,: set the comma as output filed separator (a space by default)

• sub("^[0-9]+\\s","",$3): erase numbers followed by a space at the beginning of the string $3 and print the current line (because "print" is the default action in awk)

In this way you can edit the desired column and print all the others (that in general may be many).