着色heredocs，bash [英] coloring in heredocs, bash

问题描述

如果我以前定义过这样的颜色变量:

If I have previously defined color variable like this:

txtred='\e[1;31m'

我将如何在 heredoc 中使用它:

    cat << EOM

    [colorcode here] USAGE:

EOM

我的意思是我应该写些什么来代替 [这里的颜色代码] 来呈现这种用法文字为红色? $ {txtred} 不起作用，因为这就是我在整个过程中使用的bash脚本，位于 heredoc

I mean what should I write in place of [colorcode here] to render that USAGE text red? ${txtred} won't work, as that is what I am using throughout my bash script, outside of heredoc

推荐答案

您需要一些东西来解释 cat 不会执行的转义序列.这就是为什么需要 echo -e 而不是仅仅使 echo 正常运行的原因.

You need something to interpret the escape sequence which cat won't do. This is why you need echo -e instead of just echo to make it work normally.

cat << EOM
$(echo -e "${txtred} USAGE:")
EOM

有效

，但是您也不能通过使用 textred = $(tput setaf 1)使用转义序列，然后直接使用变量.

but you could also not use escape sequences by using textred=$(tput setaf 1) and then just use the variable directly.

textred=$(tput setaf 1)

cat <<EOM
${textred}USAGE:
EOM

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