Escaping the '\' character in the replacement string in a sed expression

Question

I am trying to take a line of text like

    13) Check for orphaned Path entries

and change it to (I want the bash color codes to colorize the output, not display on the screen)

\033[32m*\033[0m Check for orphaned Path entries

with bash color codes to colorize the asterisk to make it stand out more. I have a sed command that does most of that, except it doesn't handle the color codes correctly since it sees them as references to replacement text.

What I have so far:

sed "s/ *13) \(.*\)/ \033[32m*\033[0m \1/"

which produces the following output when run on the string I gave at the beginning:

   13) Check for orphaned Path entries33[32m*  13) Check for orphaned Path entries33[0m Check for orphaned Path entries

It is taking the \0 of the \033 and replacing it with the original string. Doubling the backslashes in the replacement string doesn't make a difference; I still get the same output text.

How do I insert bash color escapes into a sed replacement expression?

Answer 1

Double the backslashes in the replacement string, AND use single instead of double quotes around the sed expression:

sed 's/ *13) \(.*\)/ \\033[32m*\\033[0m \1/'

This prevents the shell from interfering with the sed behaviour.

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Update:

Use a script to achieve color cleanly:

colorize.sh

#!/bin/sh

HIGHLIGHT=`echo -e '\033[32m'`
NORMAL=`echo -e '\033[0m'`

sed "s/ *13) \(.*\)/ $HIGHLIGHT*$NORMAL \1/" yourinputtext

Answer 2

Try this :

sed  "s/ *13) \(.*\)/ \\\\033 \1/"

i.e. slash-slash-slash-slash-033

Answer 3

Chances are that the sed you are using doesn't understand octal, but it may understand hex. Try this version to see if it works for you (using \x1b instead of \033):

sed "s/ *13) \(.*\)/ \x1b[32m*\x1b[0m \1/"

Answer 4

your '\033' is in fact a single ESC (escape) character, to output this you may use any one of the following:

• \o033
• \d027
• \x1B