Essential SSH and SCP Command Cheat Sheet

Connecting via SSH

Connect to a server (default port 22):

$ ssh [email protected]

Connect on a specific port:

$ ssh [email protected] -p 6222

Connect via PEM file (requires 0400 permissions):

$ ssh -i /path/file.pem [email protected]

See: SSH Permissions

Executing Remote Commands

Execute a remote command:

$ ssh [email protected] 'ls -l'

Invoke a local script:

$ ssh [email protected] bash < script.sh

Compress and download from a server:

$ ssh [email protected] "tar cvzf - ~/source" > output.tgz

SCP File Transfers

• Copy from remote to local: scp user@server:/dir/file.ext dest/
• Copy between two servers: scp user@server:/file user@server:/dir
• Copy from local to remote: scp dest/file.ext user@server:/dir
• Copy a whole folder: scp -r user@server:/dir dest/
• Copy all files from a folder: scp user@server:/dir/* dest/
• Copy from server folder to current folder: scp user@server:/dir/* .

Configuration Locations

SCP Options

SSH Config Sample

Host server1 
    HostName 192.168.1.5
    User root
    Port 22
    IdentityFile ~/.ssh/server1.key

Launch by alias:

$ ssh server1

See: Full Config Options

ProxyJump

$ ssh -J proxy_host1 remote_host2
$ ssh -J user@proxy_host1 user@remote_host2

Multiple jumps:

$ ssh -J user@proxy_host1:port1,user@proxy_host2:port2 user@remote_host3

SSH Copy ID

Copy public key to server:

$ ssh-copy-id user@server
$ ssh-copy-id server1
$ ssh-copy-id -i ~/.ssh/id_rsa.pub user@server

SSH Keygen

Generating Keys

$ ssh-keygen -t rsa -b 4096 -C "[email protected]"

Key Management

• Generate interactively: ssh-keygen
• Specify filename: ssh-keygen -f ~/.ssh/filename
• Generate public from private: ssh-keygen -y -f private.key > public.pub
• Change comment: ssh-keygen -c -f ~/.ssh/id_rsa
• Change passphrase: ssh-keygen -p -f ~/.ssh/id_rsa

Supported Key Types

• rsa
• ed25519
• dsa
• ecdsa

Known Hosts Management

Search known_hosts: ssh-keygen -F <ip/hostname>

Remove from known_hosts: ssh-keygen -R <ip/hostname>

Key Formats

• PEM
• PKCS8