How to enable using commands on remote host using ssh without password?

Question

i set up to use ssh between two hosts without password.

ssh log in is working fine but execute commands failed with the below erro:

**isn't allowed to be executed with process or redirect controls.**

Simple command used:

ssh remo-tehost " echo \"\test\"  >> \"/home/alarmstest.log\" "

Running trace i got:

debug1: Sending command:  echo "test"  >> "/home/alarmstest.log" 
debug2: channel 0: request exec confirm 1
debug2: fd 3 setting TCP_NODELAY
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel 0: rcvd adjust 2097152
debug2: channel_input_status_confirm: type 99 id 0
debug2: exec request accepted on channel 0
debug2: channel 0: rcvd ext data 117

there is sudosh on the remote server for the user used user:x:500:500::/home/user:/usr/local/bin/sudosh authorized_keys from the remote server + key inside -rw------- 1 user user 9092 Dec 13 07:53 authorized_keys

Answer 1

This appears to be an issue with quoting. Simply remember that whenever you want to execute a shell command over ssh then it is received by the remote shell (e.g. Bash) as, /bin/bash -c <command-line>. You need to have only one pair of quotes:

ssh remo-tehost "echo test  >> /home/alarmstest.log"

This pair is important to prevent the local shell, that is, the one you using to executing the command-line, from interpreting the parameters.

Answer 2

issue due to permission on home directory:

home directory ~, ~/.ssh directory and ~/.ssh/authorized_keys file on the remote host must be writable only by the user used 700 or 755, 775 will not work.

private key file (on the local host) neet to be readable and writable only by the user used: rw——-, 600.