I am trying to count the number of lines after a problematic row in a csv file. I am aware I can use the grep -a # syntax to output # number of lines after a match has been found. I'm only interested in the actual number of lines. I realize I could set the number to MAX_INT, pipe it into a file and do some more processing.
I'm looking for a succinct one-liner to just tell me the count.
Any suggestions?
{ grep -m1 match; grep -c ''; } <file
That will work w/ GNU grep and an lseek()able infile. The first grep will stop at 1 -match, and the second will -count every line remaining in input.
Without GNU grep:
{ sed '/match/q'; grep -c ''; } <file
Of course, w/ grep you can use any/all of its other options besides, and stopping at one match is not at all necessary.
grep -m1 match >/dev/null of course. And your second problem is a GNU sed - it doesn't reset its input offset per spec. You have to use -u w/ GNU - which is not always desirable. I could have been clearer, but my assumption was that a GNU grep and GNU sed would come in pairs. I think, also, grep -qm1 could work to shortcut the /dev/null redirect - but GNU grep does weird things w/ -q and i can't recall how those two work together.
wc -l is a little bit cheaper than grep -c ''.
Here's one way.
$ cat foo
aaa
bbb
ccc
ddd
eee
fff
$ awk '/^ddd/{a=FNR}END{print FNR-a}' foo
2
$
Another way - use of dc is a little esoteric, but seems to work nicely here:
sed -n '/problem/=;$=' prob.txt | dc -e '??r-p'
sed searches prob.txt for "problem" and the last line, and uses the = command to output the line number of both.
dc reads these two values onto the stack, reverses them, subracts and prints the difference.
Entirely with sed(albeit two command with a pipe)
sed '/ddd/,$!d' file | sed -n '$='
Deletes all the line before the line and then the next command counts the lines in the new file.
This should delete all lines up to (and including) the problemtic one and then count the remaining lines:
sed '1,/problem/d' data.txt | wc -l
