着色尾巴输出重击

Question

I have a chat script wich is using

tail -f chatlog.txt

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

chatlog.txt:

20:39 \033[4;33musername\033[0m: sowith all of my experiance
20:39 \033[4;33musername\033[0m: we shall proveil
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"

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

Answer 1

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 .