如何使用tail命令实现带颜色输出？需红色打印指定文件最后4行

Hey there! Great question—adding colored output to your tail command is totally doable with ANSI escape codes, which most modern terminals support. Here's exactly how to get the red-colored last 4 lines of FDECMP1_$$.log:

Method 1: Using tail + awk #

This is a clean, straightforward approach:

tail -4 FDECMP1_$$.log | awk '{print "\033[31m" $0 "\033[0m"}'

Let's break down what each part does:

• tail -4 FDECMP1_$$.log: Grabs the final 4 lines of your target file (the -4 flag specifies the number of lines).
• awk '{print "\033[31m" $0 "\033[0m"}': Takes each line from tail and wraps it in ANSI color codes:
  • \033[31m: Activates red text formatting.
  • $0: Represents the entire line of input from tail.
  • \033[0m: Resets the terminal back to default formatting—this is crucial, otherwise all subsequent terminal output will stay red!

Method 2: Using tail + sed #

If you prefer sed over awk, this works too:

tail -4 FDECMP1_$$.log | sed 's/^/\x1b[31m/; s/$/\x1b[0m/'

• s/^/\x1b[31m/: Adds the red color code at the start of each line (^ denotes the line beginning).
• s/$/\x1b[0m/: Adds the reset code at the end of each line ($ denotes the line ending).

Quick Note #

This relies on your terminal supporting ANSI escape sequences. Almost all modern terminals (Bash, Zsh, iTerm2, Windows Terminal, etc.) do this, but if you're using a very old or specialized terminal, it might not work (you'll see the raw escape codes instead of color).

内容的提问来源于stack exchange，提问作者Ashish P