How to truncate long matching lines returned by grep or ack

Question

I want to run ack or grep on HTML files that often have very long lines. I don\'t want to see very long lines that wrap repeatedly. But I do want to see just that portion of

Answer 1

I put the following into my .bashrc:

grepl() {
    $(which grep) --color=always $@ | less -RS
}

You can then use grepl on the command line with any arguments that are available for grep. Use the arrow keys to see the tail of longer lines. Use q to quit.

Explanation:

• grepl() {: Define a new function that will be available in every (new) bash console.
• $(which grep): Get the full path of grep. (Ubuntu defines an alias for grep that is equivalent to grep --color=auto. We don't want that alias but the original grep.)
• --color=always: Colorize the output. (--color=auto from the alias won't work since grep detects that the output is put into a pipe and won't color it then.)
• $@: Put all arguments given to the grepl function here.
• less: Display the lines using less
• -R: Show colors
• S: Don't break long lines

Answer 2

You could use the grep option -o, possibly in combination with changing your pattern to ".{0,10}<original pattern>.{0,10}" in order to see some context around it:

       -o, --only-matching
              Show only the part of a matching line that matches PATTERN.

..or -c:

       -c, --count
              Suppress normal output; instead print a count of matching  lines
              for  each  input  file.  With the -v, --invert-match option (see
              below), count non-matching lines.