在 bash 脚本中使用别名

Question

我在代码中使用别名，它第一次工作并显示当前时间，但第二次，当我调用它时，它显示过去的时间（之前显示的时间而不是当前时间）

  GNU nano 6.2                            aliases.sh                                     
#!/bin/bash

shopt -s expand_aliases
alias TODAY="date"
echo "This shell represent differences between static substitution and dynamic substitut>
echo "==============================================================================="

DATE=`date`

echo "Static substitution"
echo "Start of bash script is: $DATE"
echo "Now I'm going to sleep for one minute"
sleep 5s

echo " end of the script: $DATE"

echo "------------------------------------------------------------------------------"
echo "Dynamic Substitution"

DDATE=`TODAY`
echo " Current Date is $DDATE"
echo "Now I'm going to sleep for one minute"
sleep 30s
echo "end of script date is $DDATE"`

Answer 1

您将日期设置为变量，因此仅调用一次，然后该变量是静态引用。

你可以这样做：

echo "------------------------------------------------------------------------------"
echo "Dynamic Substitution"

echo " Current Date is $(today)"
echo "Now I'm going to sleep for one minute"
sleep 30s
echo "end of script date is $(today)"

请注意，$(...)命令替换通常优于反引号。