管道是否会阻止它的执行中途？[重复]-Doespipinglstoheadstopit'sexecutionhalfway?[duplicate]

11  

Once head has read enough lines from it's stdin (stdout of ls), then it exits and therefore closes the stdin. When that happens, the pipe is considered to be broken and ls receives a SIGPIPE signal. As a reaction to that it terminates as well, way before processing everything that it would normally do. In the case of tail, it has to wait for ls to terminate to know which X number of lines were the last ones.

一旦head从它的stdin(stdout of ls)中读取了足够的行,那么它就会退出并因此关闭stdin。当发生这种情况时,管道被认为是损坏的并且ls接收到SIGPIPE信号。作为对它的反应,它也会在处理通常所做的一切之前终止。在tail的情况下,它必须等待ls终止以知道哪些X行是最后一行。

0  

This would be more efficient as no new processes are created:

由于没有创建新进程,因此效率更高:

a=( folder/* )
echo ${a[@]:0:9}

In same cases it may be even better as you don't have to prepend folder/ if you want to do something with the result.

在相同的情况下,它可能会更好,因为您不必在文件夹前添加/如果您想对结果执行某些操作。