为什么会这样:
free | cut -c67- && free | cut -c55-61
给我缓冲区和缓存大小,但是
free -s4 | cut -c67- && free -s4 | cut -c55-61
只给我缓存大小。
为什么会这样:
free | cut -c67- && free | cut -c55-61
给我缓冲区和缓存大小,但是
free -s4 | cut -c67- && free -s4 | cut -c55-61
只给我缓存大小。
从 Bash 手册页:
SHELL GRAMMA [...] Lists AND and OR lists are sequences of one of more pipelines separated by the && and || control operators, respec‐ tively. AND and OR lists are executed with left associativity. An AND list has the form command1 && command2 command2 is executed if, and only if, command1 returns an exit status of zero.
在&&
command1 以返回值 0 退出之前,操作员不会执行 command2。
命令free -s4 | cut -c67-,56-61
更接近你想要的吗?