参考:http://wiki.jikexueyuan.com/project/shell-learning/command-substitution.htmlhtml
命令替换是指 shell 能够先执行命令,将输出结果暂时保存,在适当的地方输出.shell
格式:`command` spa
即用反引号(esc下面那个键)将命令括起来,好比htm
DATE=`date`it
echo "date is $DATE"io
输出结果:date is Mon Aug 7 15:25:05 CST 2017date