Create a "non-interactive login shell" user
I see several stackoverflow threads on difference between non-interactive and interactive and login and non-login shell. However, there is no clear answer on being able to create/designate a "non-interactive login shell" for a user. I see some reference "disabling" (or lock) a user account but thats not what I want. I need to be able to do remotely something like:
ssh user@hostname somecommandI tried the useradd "-s /usr/sbin/nologin" but its not working if I am trying to execute a command like above. I get output like (trying to use user name "test_nl" to localhost and execute command "pwd"):
my_user@ubuntu:~$ ssh -i test_nl test_nl@localhost -vvvv pwd
OpenSSH_7.2p2 Ubuntu-4ubuntu2.7, OpenSSL 1.0.2g 1 Mar 2016
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "localhost" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to localhost [::1] port 22.
debug1: Connection established.
debug1: identity file test_nl type 1
debug1: key_load_public: No such file or directory
debug1: identity file test_nl-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.7
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2p2 Ubuntu-4ubuntu2.7
debug1: match: OpenSSH_7.2p2 Ubuntu-4ubuntu2.7 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to localhost:22 as 'test_nl'
debug3: hostkeys_foreach: reading file "/home/my_user/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/my_user/.ssh/known_hosts:4
debug3: load_hostkeys: loaded 1 keys from localhost
debug3: order_hostkeyalgs: prefer hostkeyalgs: ,,,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: ,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: ,,,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,,,ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: ,aes128-ctr,aes192-ctr,aes256-ctr,,,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc
debug2: ciphers stoc: ,aes128-ctr,aes192-ctr,aes256-ctr,,,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc
debug2: MACs ctos: ,,,,,,,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: ,,,,,,,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,,zlib
debug2: compression stoc: none,,zlib
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: ,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: ,aes128-ctr,aes192-ctr,aes256-ctr,,
debug2: ciphers stoc: ,aes128-ctr,aes192-ctr,aes256-ctr,,
debug2: MACs ctos: ,,,,,,,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: ,,,,,,,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,
debug2: compression stoc: none,
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm:
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: MAC: <implicit> compression: none
debug1: kex: client->server cipher: MAC: <implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:qwLgqbgRRRXK9MxbkWmHziRek34pW6nvDiE0fYV7ImI
debug3: hostkeys_foreach: reading file "/home/my_user/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/my_user/.ssh/known_hosts:4
debug3: load_hostkeys: loaded 1 keys from localhost
debug1: Host 'localhost' is known and matches the ECDSA host key.
debug1: Found key in /home/my_user/.ssh/known_hosts:4
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug2: key: test_nl (0x56156682cd00), explicit
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: test_nl
debug3: send_pubkey_test
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 60
debug1: Server accepts key: pkalg rsa-sha2-512 blen 279
debug2: input_userauth_pk_ok: fp SHA256:RFDBiNfj35+57Lllaccu8Um6qPUuP7I3jDrPWgNRKNU
debug3: sign_and_send_pubkey: RSA SHA256:RFDBiNfj35+57Lllaccu8Um6qPUuP7I3jDrPWgNRKNU
debug3: send packet: type 50
debug3: receive packet: type 52
debug1: Authentication succeeded (publickey).
Authenticated to localhost ([::1]:22).
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug3: send packet: type 90
debug1: Requesting
debug3: send packet: type 80
debug1: Entering interactive session.
debug1: pledge: network
debug3: receive packet: type 80
debug1: client_input_global_request: rtype want_reply 0
debug3: receive packet: type 91
debug2: callback start
debug2: fd 3 setting TCP_NODELAY
debug3: ssh_packet_set_tos: set IPV6_TCLASS 0x10
debug2: client_session2_setup: id 0
debug2: channel 0: request pty-req confirm 1
debug3: send packet: type 98
debug1: Sending environment.
debug3: Ignored env XDG_SESSION_ID
debug3: Ignored env TERM
debug3: Ignored env SHELL
debug3: Ignored env SSH_CLIENT
debug3: Ignored env OLDPWD
debug3: Ignored env SSH_TTY
debug3: Ignored env USER
debug3: Ignored env LS_COLORS
debug3: Ignored env VIRTUAL_ENV
debug3: Ignored env LIBVIRT_DEFAULT_URI
debug3: Ignored env MAIL
debug3: Ignored env PATH
debug3: Ignored env PWD
debug1: Sending env LANG = en_US.UTF-8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env PS1
debug3: Ignored env SHLVL
debug3: Ignored env HOME
debug3: Ignored env LOGNAME
debug3: Ignored env XDG_DATA_DIRS
debug3: Ignored env SSH_CONNECTION
debug3: Ignored env LESSOPEN
debug3: Ignored env XDG_RUNTIME_DIR
debug3: Ignored env LESSCLOSE
debug3: Ignored env _
debug2: channel 0: request shell confirm 1
debug3: send packet: type 98
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 0
debug2: PTY allocation request accepted on channel 0
debug2: channel 0: rcvd adjust 2097152
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 0
debug2: shell request accepted on channel 0
Welcome to Ubuntu 16.04.6 LTS (GNU/Linux 4.4.0-142-generic x86_64) * Documentation: * Management: * Support:
142 packages can be updated.
94 updates are security updates.
Last login: Thu Sep 5 15:54:47 2019 from ::1
This account is currently not available.
debug3: receive packet: type 96
debug2: channel 0: rcvd eof
debug2: channel 0: output open -> drain
debug2: channel 0: obuf empty
debug2: channel 0: close_write
debug2: channel 0: output drain -> closed
debug3: receive packet: type 98
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug3: receive packet: type 98
debug1: client_input_channel_req: channel 0 rtype reply 0
debug2: channel 0: rcvd eow
debug2: channel 0: close_read
debug2: channel 0: input open -> closed
debug3: receive packet: type 97
debug2: channel 0: rcvd close
debug3: channel 0: will not send data after close
debug2: channel 0: almost dead
debug2: channel 0: gc: notify user
debug2: channel 0: gc: user detached
debug2: channel 0: send close
debug3: send packet: type 97
debug2: channel 0: is dead
debug2: channel 0: garbage collecting
debug1: channel 0: free: client-session, nchannels 1
debug3: channel 0: status: The following connections are open: #0 client-session (t4 r0 i3/0 o3/0 fd -1/-1 cc -1)
debug3: send packet: type 1
Connection to localhost closed.
Transferred: sent 3020, received 3592 bytes, in 0.2 seconds
Bytes per second: sent 15345.1, received 18251.5
debug1: Exit status 1I still see option it triggering interactive shell. How do I disable it (or login 'non-interactively' and execute somecommand (in this case pwd). FYI my /etc/passwd is:
my_user@ubuntu:~$ cat /etc/passwd | grep test_
test_nl:x:1002:1002:,,,:/home/test_nl:/usr/sbin/nologin
my_user@ubuntu:~$ 
