MY_PATH = $(readlink -f $ YOUR_ARG)将解析相对路径，例如“./”和“../”
原文链接：https://www.f2er.com/bash/390919.html考虑这一点(source)：
#!/bin/bash
dir_resolve()
{
cd "$1" 2>/dev/null || return $? # cd to desired directory; if fail,quell any error messages but return exit status
echo "`pwd -P`" # output full,link-resolved path
}
# sample usage
if abs_path="`dir_resolve \"$1\"`"
then
echo "$1 resolves to $abs_path"
echo pwd: `pwd` # function forks subshell,so working directory outside function is not affected
else
echo "Could not reach $1"
fi
