命令或echo命令中的别名(Linux Ubuntu Bash)

Question

我创建了一个名为usernum的永久别名，如下所示:

usernum='who | wc -l'

它只是返回有多少用户。我正在尝试将以下命令放入cronjob中。

echo "The following number of users are logged in: $usernum"

但是，这只回显:

The following number of users are logged in:

如何使命令可以在带有替换的echo命令的字符串中使用?

Answer 1

更改为:

alias usernum='who | wc -l'
echo "The following number of users are logged in: $(usernum)"
The following number of users are logged in: 1

Answer 2

使用函数代替别名:

usernum() { who | wc -l ; }

然后调用函数:

echo "$(usernum) users are logged in."