问题
ssh -t remotehost vim /tmp/x.txt
I know that I can run a command like the above.
But I would like to be able to run any local bash code in a remote machine. For this reason, I'd like to call the remote 'bash -s' so that can process any local bash code.
ssh -t remotehost 'bash -s' <<< vim /tmp/x.txt
However, the above example shows "Pseudo-terminal will not be allocated because stdin is not a terminal." Is there any way to let ssh take local bash code via stdin and run it via the remote 'bash -s'? Thanks.
回答1:
ssh -t remotehost 'bash -s' <<< vim /tmp/x.txt
You're getting the "Pseudo-terminal will not be allocated..." message because you're running ssh with a single -t option, when the standard input to the ssh process isn't a TTY. ssh prints that message specifically in this case. The documentation for -t says:
-t
Force pseudo-terminal allocation. This can be used to execute arbitrary screen-based programs on a remote machine, which can be very useful, e.g. when implementing menu services. Multiple -t options force tty allocation, even if ssh has no local tty.
The -t command-line option is related to the ssh configuration option RequestTTY:
RequestTTY
Specifies whether to request a pseudo-tty for the session. The argument may be one of: no (never request a TTY), yes (always request a TTY when standard input is a TTY), force (always request a TTY) or auto (request a TTY when opening a login session). This option mirrors the -t and -T flags for ssh(1).
A single -t is equivalent to "RequestTTY yes", while two of them is equivalent to "RequestTTY force".
If you want your remote command(s) to run with a TTY, then specify -t twice:
ssh -tt remotehost 'bash -s' <<< vim /tmp/x.txt
or
ssh -t -t remotehost 'bash -s' <<< vim /tmp/x.txt
ssh will allocate a TTY for the remote system and it won't print that message.
If the command(s) being run on the remote system don't require a TTY, you can leave the -t option out:
ssh remotehost 'bash -s' <<< vim /tmp/x.txt
回答2:
I believe the following might suit your purposes:
vim /tmp/x.txt ; ssh remotehost 'bash -s' < /tmp/x.txt
The first expression (vim ...) allows you to specify the commands you want to execute remotely as a local file called /tmp/x.txt; the second expression (ssh ...) calls the remote bash interpreter, and sends the contents of your local file to it for execution. Note that you do not need the -t option for ssh in this case (which gave rise to the pseudo-terminal warning), and that you do not need to use a here string (<<<) but can use the normal file input operator (<).
This solution seems to work for, e.g., the following file contents:
echo These commands are being executed on $HOSTNAME
echo This is a second command
来源：https://stackoverflow.com/questions/48648572/how-to-deal-with-pseudo-terminal-will-not-be-allocated-because-stdin-is-not-a-t