I have a file that looks like this:
hello even evening how are they? ... I want to count the occurences of the letter e but without taking the letter e of the 1st field under consideration. I've used this command but it doesn't work.
awk 'for(i=2;i<=NR;i++) match($i,/e/){sum++}END{print sum}' With flexible gsub feature:
awk '{ $1=""; cnt += gsub("e", "") }END{ print cnt }' file The
gsub()function returns the number of substitutions made
awk '{ $1=""; print gsub("e", "") }' file var=$(awk ...) Your loop looks correct apart from using NR (number of the current record/line) in place of NF (number of fields in the current record/line), but it would be easier to count with gsub():
$ awk '{ for (i=2; i<=NF; ++i) sum+=gsub("e","e",$i) } END { print sum }' file 6 The gsub() function returns the number of times it makes a substitution.
In Perl, you would use the tr operator in a similar way
$ perl -ane 'shift @F; map($sum += tr/e/e/, @F); END { print $sum, "\n" }' file 6 Or, you could just use the other basic utilities from the tool chest:
$ cut -d ' ' -f 2- file | tr -dc 'e' | wc -m 6 This cuts off everything before the first space character, deletes everything that isn't an e, and then counts the number of characters that are left.
Some more approaches:
coreutils
$ cut -d' ' -f 2- file | fold -w1 | grep -c e 6 Perl (basically a golfed version of what Kusalananda gave)
$ perl -lane 'map{$k+=tr/e//}@F[1..$#F];}{print $k ' file perl -lane 'map{$k+=s/e/e/g}@F[1..$#F]}{print $k' file 6 GNU grep + awk (just for fun)
$ grep -oP '^\S+\K.*' file | awk -F'e' '{k+=NF-1}END{print k}' 6 You could do this:
$ perl -lpe '/\S\s/g;$s+=()=/e/g}{print $s' file 6 
$ awk '{sum += gsub(/e/,"&") - gsub(/e/,"&",$1)} END{print sum+0}' file 6 
gsub(/e/,"&") instead of gsub(/e/,"") or is it just habit, and general good practice? es left for the 2nd gsub() to count. I tend to always use "&" by default unless I need to remove the matched strings so I don't trip myself up if I need to print the original record or do anything else that requires the content to be as read.