CODEWITHSUNDEEP
linuxbash
jakic
jakic

Reputation: 23

coloring tail output bash

I have a chat script which is using

tail -f chatlog.txt

to display the chat. The messages are written so that when you echo it, it outputs as colored text.

chatlog.txt:

20:39 \033[4;33musername\033[0m: so with all of my experience
20:39 \033[4;33musername\033[0m: we shall prevail
20:40 \033[4;33musername\033[0m: the taxi jobs are very
20:40 \033[4;33musername\033[0m: yes
21:02 \033[4;34mJacob\033[0m has joined the chat!

if I display using this code it works fine:

var=$(tail chatlog.txt)
echo -e "$var"

output of the code

But if I display it with tail -f chatlog.txt there is no color. I have tried other solutions but none seemed to work.

Upvotes: 0

Views: 185

Answers (1)

Charles Duffy
Charles Duffy

Reputation: 295383

Your output contains literal escape sequences; thus, all you need is a program which will recognize those and replace them with the characters they refer to. In POSIX-compliant shells, printf %b will perform this operation.

Thus:

tail -f chatlog.txt | while IFS= read -r line; do printf '%b\n' "$line"; done

See BashFAQ #1 for a general discussion of the while read mechanism. To call out some of the important points:

  • Using IFS= prevents leading and trailing whitespace from being trimmed from lines.
  • Using the -r argument to read prevents literal backslashes from being removed by read.

Upvotes: 1

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