命令替换内部的bash逻辑 [英] bash logic inside command substitution

问题描述

我在登录时会显示一个小横幅

I have a little banner that I display at login

fignow() { figlet -w $(tput cols) $(date +"%b %d, Week %V"); figlet -w $(tput cols) -f univers $(date +"%H:%M"); }

如果为了获得 univers 而安装了其他字体，此方法就可以正常工作，但这不是默认安装的一部分，因此我可以执行以下操作:

This works fine if the additional fonts are installed to get univers, but that's not part of the default installation, so I can do the following:

fignow() { figlet -w $(tput cols) $(date +"%b %d, Week %V"); if [ -f /usr/share/figlet/univers.flf ]; then figlet -w $(tput cols) -f univers $(date +"%H:%M"); else figlet -w $(tput cols) $(date +"%H:%M"); fi; }

这也可以正常工作，但是我很好奇是否可以删除 if/else/fi ，并且逻辑可以在命令本身内部完成，即:

This also works fine, but I was curious if the if/else/fi could be removed and the logic could be done inside the command itself, i.e. something like:

fignow() { figlet -w $(tput cols) $(date +"%b %d, Week %V"); figlet -w $(tput cols) -f $(use-univers-or-failback-to-standard.flf-if-univers.flf-is-not-available) $(date +"%H:%M"); }

有可能吗?

推荐答案

我建议使用 figlist 避免对主题路径进行硬编码:

I suggest to use figlist to avoid hardcoding the themes path:

figlet -w "$(tput cols)" -f "$((figlist | /bin/grep -hw universe) || echo "standard")" "foo"

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