When attempting to run a remote binary using sudo on the remote box:
ssh remotehost "sudo ./binary"
I see this error:
sudo: no tty present and no askpass program specified
How can I work around this?
asked Apr 15, 2013 at 14:32
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6 Answers
A simple way is to specify -t:
ssh -t remotehost "sudo ./binary"
From the man page:
Force pseudo-tty 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.
I cannot explain exactly why this works, and there may be a better way. I'd like to hear about it if so :)
@psusi explains why this works in a comment below.
answered Apr 15, 2013 at 14:32
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18It works because
sudorequires a tty to prompt for a password, and when specifying commands to run tossh, it doesn't allocate one by default since this is normally used to run non interactive commands that may transfer binary data, which can trip up the tty.– psusiApr 15, 2013 at 14:39 -
@psusi Do you know the answer to this related question? unix.stackexchange.com/questions/110841– trusktrJan 25, 2014 at 3:38
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Question:
How can I work around this?
sudo: no tty present and no askpass program specified
Alternate Answer
As an alternative, try:
sudo -S ./[yourExecutable]
This directs sudo to read the password from the standard input, stdin.
Scenarios where this Helps
In chroot environments, these other answers may not work correctly ... perhaps because:
- /etc/shadow vs /etc/passwd conflict not allowing the user to enter a password.
- In a chroot-ed environment, access to tty1 can be a bit glitchy, and ctrl-alt f2 -- to tty2 is unfeasible, because it is a tty of the non-chroot-ed environment.
For example: Manually installing / repairing linux or the bootloader, using a chroot environment, (such as Archlinux and arch-chroot).
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I get a sudo: ./binary: command not found error when I run sudo -S ./binary, what gives? Aug 31, 2019 at 21:32
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1@AjitGoel it was just an example. Replace ./binary with the command you want to run. Jan 13, 2020 at 10:24
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It fails, because sudo is trying to prompt on root password and there is no pseudo-tty allocated.
You've to either log-in as root or set-up the following rules in your /etc/sudoers
(or: sudo visudo):
# Members of the admin group may gain root privileges
%admin ALL=(ALL) NOPASSWD:ALL
Then make sure that your user belongs to admin group (or wheel).
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whilst this is not true (no evidence is given for this, and users in the admin group with that code in centos and ubuntu systems still get the error), it is a great tip for remoting to create groups and rules based upon those groups for escalated tasks– MrMeseesDec 2, 2016 at 23:02
You need to define terminal/application that will read the password. There are two variants:
export SUDO_ASKPASS=/usr/libexec/openssh/ssh-askpassvim /etc/sudoers(Defaults visiblepw)
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13Is it not better to use
visudoinstead ofvim /etc/sudoersin order to avoid potentially locking yourself out of your machine due to having made an error in your edit? May 16, 2014 at 19:57
In my case I've received this error because I wasn't specifying a command that I would like to use as root in the sudoers
Something like
/etc/sudoers.d/myuser:
myuser ALL=(root) NOPASSWD: \
/bin/ls -la
worked for me
You can also create a file like "sudo_shutdown" in /etc/sudoers.d, with content:
# Allow admins to shutdown without pass
%adm ALL=(ALL) NOPASSWD: /sbin/shutdown
This allows users which are in the adm group to shutdown without a password.
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