4 ways to implement SSH automatic login _linux shell

1. Automatic Ssh/scp method

A is a local host (that is, a machine used to control other hosts);
b is a remote host (that is, a controlled machine server), if IP is 192.168.60.110;
Both A and B systems are Linux.

To run a command on a:
# ssh-keygen-t RSA (three consecutive returns, that is, the public and private keys are generated locally, no password is set)
# SSH root@192.168.60.110 "mkdir. SSH" (Requires a password)
# SCP ~/.ssh/id_rsa.pub root@192.168.60.110:.ssh/id_rsa.pub (need to enter password)

The Order on B:
# Touch/root/.ssh/authorized_keys (If this file is already present, skip this one)
# cat/root/.ssh/id_rsa.pub >>/root/.ssh/authorized_keys (append id_rsa.pub content to Authorized_keys)

Back to a machine:
# SSH root@192.168.60.110 (no password required, login successful)

2. Control n machines as described above automatic login

That requires n-pair keys (keys and public keys), and the Ssh-keygen command can change the name of the key pair arbitrarily, such as:
# ssh-keygen-t RSA
Generating public/private RSA key pair.
Enter file in which to save the key (/ROOT/.SSH/ID_RSA):/root/.ssh/id_rsa_192.168.60.110

The private key and the public key name are: Id_rsa_192.168.60.110 and id_rsa_192.168.60.110.pub, and then the contents of the Id_rsa_192.168.60.110.pub file are appended to the sever ~/. Ssh/authorized_keys file, and finally, locally use the SSH command-i parameter to specify the local key and log in:
# ssh-i/root/.ssh/id_rsa_192.168.60.110 someone@192.168.60.110

The SCP is the same.
# scp-i/root/.ssh/id_rsa_192.168.60.110 filename someone@192.168.60.110:/home/someone

Add two lines to the file. BASHRC, and do the same thing each time without typing this long command:
Alias Sshcell= ' ssh-i/root/.ssh/id_rsa_192.168.60.110 someone@192.168.60.110 '
Alias scpcell= ' scp-i/root/.ssh/id_rsa_192.168.60.110 filename someone@192.168.60.110:/home/someone '

In this way, type the instructions directly to implement SSH and SCP automatic logon:
# Sshcell
# Scpcell

3. Automatic SSH/SCP Script

If you need to from a, to B, and then to C, then need SSH and SCP two times, is more troublesome.
SSH Automatic Login:
#!/usr/bin/expect-f
Set Timeout 30
Spawn ssh Weiqiong@b
Expect "Password:"
Send "PPPPPPR"
Expect "]*"
Send "SSH weiqiong@cr"
Expect "Password:"
Send "PPPPPPR"
Interact

SCP copies files from a to C:
#!/usr/bin/expect-f
Set Timeout 300
Set file [lindex $argv 0]
Spawn SCP $file Weiqiong@b:/home/weiqiong
Expect "Password:"
Send "PPPPPPR"
Expect "]*"
Spawn ssh Weiqiong@b
Expect "Password:"
Send "PPPPPPR"
Expect "]*"
Send "SCP $file weiqiong@c:/home/weiqiongr"
Expect "Password:"
Send "PPPPPPR"
Expect "]*"
Exit
Interact

SCP copies files from C to a:
#!/usr/bin/expect-f
Set Timeout 300
Set file [lindex $argv 0]
Spawn ssh Weiqiong@b
Expect "Password:"
Send "PPPPPPR"
Expect "]*"
Send "SCP weiqiong@c:/home/weiqiong/$file. R"
Expect "Password:"
Send "PPPPPPR"
Expect "]*"
Send "Exitr"
Expect "]*"
Spawn SCP weiqiong@b:/home/weiqiong/$file.
Expect "Password:"
Send "PPPPPPR"
Interact

4. Establishment of SSH/SCP Channel

For example, my machine is a, intermediate server is B, target server is C
From a can ssh to B, from B can ssh to C, but a cannot ssh directly to C
Now demonstrates using SSH channel technology to transfer files directly from A to C

1. Ssh-l1234:c:22 userid@b
Input B ' s password
(1234 is a free port for native A, which requires root user rights on machine A, and actually establishes a channel on the native 1234 port)

2. Open a new console and type:
scp-p1234 filename Userid@localhost:
Input C ' s password