script - Some Unix commands fail with “<command> not found”, when executed using Python Paramiko exec_command
ssh using python script (1)
by default does not run shell in "login" mode and does not allocate a pseudo terminal for the session. As a consequence a different set of startup scripts is (might be) sourced (particularly for non-interactive sessions,
is not sourced), than in your regular interactive SSH session. And/or different branches in the scripts are taken, based on an absence/presence of
Possible solutions (in preference order):
Fix the command not to rely on a specific environment. Use a full path to
sesuin the command. E.g.:
If you do not know the full path, on common *nix systems, you can use
which sesucommand in your interactive SSH session.
Fix your startup scripts to set the
PATHthe same for both interactive and non-interactive sessions.
Try running the script explicitly via login shell (use
--loginswitch with common *nix shells):
bash --login -c "sesu test"
If the command itself relies on a specific environment setup and you cannot fix the startup scripts, you can change the environment in the command itself. Syntax for that depends on the remote system and/or the shell. In common *nix systems, this works:
PATH="$PATH;/path/to/sesu" && sesu test
Another (not recommended) approach is to force the pseudo terminal allocation for the "exec" channel using the
stdin,stdout,stderr=ssh.exec_command('sesu test', get_pty=True)
Using the pseudo terminal to automate a command execution can bring you nasty side effects. See for example Is there a simple way to get rid of junk values that come when you SSH using Python's Paramiko library and fetch output from CLI of a remote machine?
- Environment variable differences when using Paramiko
- Certain Unix commands fail with "... not found", when executed through Java using JSch
I am trying to run
command in Unix server from Python with the help of Paramiko
. However when I am running this command
, I am getting
sh: sesu: not found
When I am running simple
command it giving me desired output. Only with
command it is not working fine.
This is how my code looks like:
import paramiko host = host username = username password = password port = port ssh=paramiko.SSHClient() ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy()) ssh.connect(ip,port,username,password) stdin,stdout,stderr=ssh.exec_command('sesu test') stdin.write('Password') stdin.flush() outlines=stdout.readlines() resp=''.join(outlines) print(resp)