shell中的while read 与 ssh 与多线程
今天在写运维工具的时候，while read line之后，
再调用ssh去远程服务器上执行命令，然后while内循环只执行了一次就退出了…
cat $hostfile | while read line
do
echo $line ":"
ssh "$line" "w"
echo "===="
done
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颇为不解。只好gg.
然后发现ssh会去读stdin… 我那个while read也会读stdin..父子进程读到一起去了…
man之后，发现参数-n:
-n Redirects stdin from /dev/null (actually, prevents reading from stdin). This must be used when ssh is run in the background. A common trick is to use this to run X11 programs on a remote machine.
For example, ssh -n shadows.cs.hut.fi emacs & will start an emacs on shadows.cs.hut.fi, and the X11 connection will be automatically forwarded over an … |