touch是用来修改时间的
cat才是用来查看文件内容的,追加内容到文件
cat /root/.ssh/id_rsa.pub >> /root/.ssh/authorized_keys (将id_rsa.pub的内容追加到authorized_keys 中)
echo是用来写文件的
echo "# wow" >> README.md
echo $PATH查看内容:
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin