I'm trying to get the number of matches (in this case occurrences of { or }) in each line of a .tex file.
I know that the -o flag returns only the match, but it returns each match on a new line, even combined with the -n flag. I don't know of anything I could pipe this through to count the repeats. The -c flag only returns the total number of matches in the entire file - maybe I could pipe one line at a time to grep?
grep -o -n '[{}]' <filename> | cut -d : -f 1 | uniq -c
The output will be something like:
3 1
1 2
Meaning 3 occurrences in the first line and 1 in the second.
Taken from https://stackoverflow.com/a/15366097/3378354 .
sort isn't strictly necessary as grep's output is sorted by line number, but I guess it's good practice before uniq.
regex because the regex is the easy part.
sort -n? Doesn't it come out in line number order anyway?
After reading various solutions, I think this is the easiest approach to the problem:
while read i; do echo $i |grep -o "matchingString"| wc -l; done < input.txt
grep -o "matchingString" <<< $i | wc -l.
Commented
Dec 20, 2015 at 5:57
Is using grep a requirement? Here’s an alternative:
sed 's/[^{}]//g' your_file | awk '{print NR, length }'
The sed strips out all characters other than { and }
(i.e., leaving only { and } characters),
and then the awk counts the characters on each line (which are just the { and } characters).
To suppress lines with no matches,
sed 's/[^{}]//g' your_file | awk '/./ {print NR, length }'
Note that my solution assumes (requires) that the strings you are looking for are single characters. Moebius’s answer is more easily adapted to multi-character strings. Also, neither of our answers excludes quoted or escaped occurrences of the characters/strings of interest; e.g.,
{ "nullfunc() {}" }
would be considered to contain four brace characters.
grep wasn't really a requirement, it was just where I started looking for a solution, because it gave me something close. I've never had a need for awk, so had I not used the answer above I'd have used this as a chance to experiment -- I may still. What I failed to make clear (but it doesn't affect either answer) is that I wanted to run the script once per bracket, to help me track down a mismatch (in LaTeX source, here for a table) where most pairs occur in a single line.
sed 's/{[^{}]*}//g' your_file | grep –n '[{}]', where the sed strips out (matched) pairs. If you have nested pairs, use sed 's/{[^{}]*}//g;s/{[^{}]*}//g;s/{[^{}]*}//g;…' …, repeating the s/{[^{}]*}//g as many times as your deepest nesting.
Commented
Jun 16, 2014 at 16:41
AWK can do this by itself, piping multiple processes is not necessary.
awk '{print NR " " gsub(/[{}]/, "")}'
Example:
$ printf 'test{}\n abc\n }{{}\n xyz}' | awk '{print NR " " gsub(/[{}]/, "")}'
1 2
2 0
3 4
4 1
The grep count option -c is a con job. It does not return the total count you expect (it is actually just a line count, not a match count).
$ printf 'test{}\n abc\n }{{}\n xyz}' | grep -con "[{}]"
3
awk can get a total count like this:
$ printf 'test{}\n abc\n }{{}\n xyz}' | awk -F"[{}]" '{c+=NF-1} END {print c}'
7
Using awk you can search for the occurrence of a string, show the number of times it was found and the linenumber on which it was found. Here I wanted to see only those lines that have the search string more than once. As input I'm using man page for ls. I put the search string (here: 'of') in a variable.
s='of'; man ls | awk -v s="${s}" '{ if ($0 ~ s) { k = split($0, ar, s); if (k > 2) { print NR, k-1, $0 }}}' | grep "${s}"
Output:
32 2 -c with -lt: sort by, and show, ctime (time of last modification of file status information); with -l: show ctime and sort by name; otherwise: sort by ctime, newest first
180 2 The SIZE argument is an integer and optional unit (example: 10K is 10*1024). Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000). Binary prefixes can be used, too: KiB=K,
The grep statement is used to colorize the search string (not visible here).
