Count the number of occurrences of a string using sed?

Question

I have a file which contains "title" written in it many times. How can I find the number of times "title" is written in that file using the sed command provided that "title" is the first string in a line? e.g.

# title title title 

should output the count = 2 because in first line title is not the first string.

Update

I used awk to find the total number of occurrences as:

awk '$1 ~ /title/ {++c} END {print c}' FS=: myFile.txt 

But how can I tell awk to count only those lines having title the first string as explained in example above?

Answer 1

Never say never. Pure sed (although it may require the GNU version).

#!/bin/sed -nf # based on a script from the sed info file (info sed) # section 4.8 Numbering Non-blank Lines (cat -b) # modified to count lines that begin with "title"  /^title/! be  x /^$/ s/^.*$/0/ /^9*$/ s/^/0/ s/.9*$/x&/ h s/^.*x// y/0123456789/1234567890/ x s/x.*$// G s/\n// h  :e  $ {x;p} 

Explanation:

#!/bin/sed -nf # run sed without printing output by default (-n) # using the following file as the sed script (-f)  /^title/! be        # if the current line doesn't begin with "title" branch to label e  x                   # swap the counter from hold space into pattern space /^$/ s/^.*$/0/      # if pattern space is empty start the counter at zero /^9*$/ s/^/0/       # if pattern space starts with a nine, prepend a zero s/.9*$/x&/          # mark the position of the last digit before a sequence of nines (if any) h                   # copy the marked counter to hold space s/^.*x//            # delete everything before the marker y/0123456789/1234567890/   # increment the digits that were after the mark x                   # swap pattern space and hold space s/x.*$//            # delete everything after the marker leaving the leading digits G                   # append hold space to pattern space s/\n//              # remove the newline, leaving all the digits concatenated h                   # save the counter into hold space  :e                  # label e  $ {x;p}             # if this is the last line of input, swap in the counter and print it 

Here are excerpts from a trace of the script using sedsed:

$ echo -e 'title\ntitle\nfoo\ntitle\nbar\ntitle\ntitle\ntitle\ntitle\ntitle\ntitle\ntitle\ntitle' | sedsed-1.0 -d -f ./counter  PATT:title$ HOLD:$ COMM:/^title/ !b e COMM:x PATT:$ HOLD:title$ COMM:/^$/ s/^.*$/0/ PATT:0$ HOLD:title$ COMM:/^9*$/ s/^/0/ PATT:0$ HOLD:title$ COMM:s/.9*$/x&/ PATT:x0$ HOLD:title$ COMM:h PATT:x0$ HOLD:x0$ COMM:s/^.*x// PATT:0$ HOLD:x0$ COMM:y/0123456789/1234567890/ PATT:1$ HOLD:x0$ COMM:x PATT:x0$ HOLD:1$ COMM:s/x.*$// PATT:$ HOLD:1$ COMM:G PATT:\n1$ HOLD:1$ COMM:s/\n// PATT:1$ HOLD:1$ COMM:h PATT:1$ HOLD:1$ COMM::e COMM:$ { PATT:1$ HOLD:1$ PATT:title$ HOLD:1$ COMM:/^title/ !b e COMM:x PATT:1$ HOLD:title$ COMM:/^$/ s/^.*$/0/ PATT:1$ HOLD:title$ COMM:/^9*$/ s/^/0/ PATT:1$ HOLD:title$ COMM:s/.9*$/x&/ PATT:x1$ HOLD:title$ COMM:h PATT:x1$ HOLD:x1$ COMM:s/^.*x// PATT:1$ HOLD:x1$ COMM:y/0123456789/1234567890/ PATT:2$ HOLD:x1$ COMM:x PATT:x1$ HOLD:2$ COMM:s/x.*$// PATT:$ HOLD:2$ COMM:G PATT:\n2$ HOLD:2$ COMM:s/\n// PATT:2$ HOLD:2$ COMM:h PATT:2$ HOLD:2$ COMM::e COMM:$ { PATT:2$ HOLD:2$ PATT:foo$ HOLD:2$ COMM:/^title/ !b e COMM:$ { PATT:foo$ HOLD:2$ . . . PATT:10$ HOLD:10$ PATT:title$ HOLD:10$ COMM:/^title/ !b e COMM:x PATT:10$ HOLD:title$ COMM:/^$/ s/^.*$/0/ PATT:10$ HOLD:title$  COMM:/^9*$/ s/^/0/ PATT:10$ HOLD:title$ COMM:s/.9*$/x&/ PATT:1x0$ HOLD:title$ COMM:h PATT:1x0$ HOLD:1x0$ COMM:s/^.*x// PATT:0$ HOLD:1x0$ COMM:y/0123456789/1234567890/ PATT:1$ HOLD:1x0$ COMM:x PATT:1x0$ HOLD:1$ COMM:s/x.*$// PATT:1$ HOLD:1$ COMM:G PATT:1\n1$ HOLD:1$ COMM:s/\n// PATT:11$ HOLD:1$ COMM:h PATT:11$ HOLD:11$ COMM::e COMM:$ { COMM:x PATT:11$ HOLD:11$ COMM:p 11 PATT:11$ HOLD:11$ COMM:} PATT:11$ HOLD:11$ 

The ellipsis represents lines of output I omitted here. The line with "11" on it by itself is where the final count is output. That's the only output you'd get when the sedsed debugger isn't being used.