Colorized grep — viewing the entire file with highlighted matches

Question

I find grep\'s --color=always flag to be tremendously useful. However, grep only prints lines with matches (unless you ask for context lines). Give

Answer 1

The -z option for grep is also pretty slick!

cat file1 | grep -z "pattern"

Answer 2

It might seem like a dirty hack.

grep "^\|highlight1\|highlight2\|highlight3" filename

Which means - match the beginning of the line(^) or highlight1 or highlight2 or highlight3. As a result, you will get highlighted all highlight* pattern matches, even in the same line.

Answer 3

To highlight patterns while viewing the whole file, h can do this.

Plus it uses different colors for different patterns.

cat FILE | h 'PAT1' 'PAT2' ...

You can also pipe the output of h to less -R for better reading.

To grep and use 1 color for each pattern, cxpgrep could be a good fit.

Answer 4

Alternatively you can use The Silver Searcher and do

ag <search> --passthrough

Answer 5

You can also create an alias. Add this function in your .bashrc (or .bash_profile on osx)

function grepe {
    grep --color -E "$1|$" $2
}

You can now use the alias like this: "ifconfig | grepe inet" or "grepe css index.html".

(PS: don't forget to source ~/.bashrc to reload bashrc on current session)

Answer 6

Here is a shell script that uses Awk's gsub function to replace the text you're searching for with the proper escape sequence to display it in bright red:

#! /bin/bash
awk -vstr=$1 'BEGIN{repltext=sprintf("%c[1;31;40m&%c[0m", 0x1B,0x1B);}{gsub(str,repltext); print}' $2

Use it like so:

$ ./cgrep pattern [file]

Unfortunately, it doesn't have all the functionality of grep.

For more information , you can refer to an article "So You Like Color" in Linux Journal