SSH Tips to Remember

Apr 18, 2021 · 4 mins read

SSH stands for Secure Shell. It is both a network protocol and a network tool for secure network communications. It can be used for connecting to remote servers for executing commands and transferring files between computers.

In this post, I’ll share tips on how I use SSH for various tasks in my day to day work and how it helps me to get the job done on remote servers.

Basic SSH

To connect to a remote server and use its terminal, execute

$ ssh the_user@domain.com 
# or with IP
$ ssh the_user@10.100.1.10
# or if ssh is served on different port
$ ssh the_user@10.100.1.10 -p 2222

After executing, you’ll be asked for a password, enter it and boom! You are now connected to the remote.

Passwordless SSH

For passwordless SSH we need to create a private and public key pair in the client PC. To do that, execute

$ ssh-keygen -t rsa
Enter file in which to save the key (/home/john/.ssh/id_rsa): #Enter a path or keep default
Enter passphrase (empty for no passphrase): # Keep empty
Enter same passphrase again: # Keep empty

This will create a public and a private pair key in your mentioned path. Copy the contents of the file ending in .pub to .ssh/authorized_keys of the remote server.

Alternatively, you could run the following to automatically do that.

$ ssh-copy-id -i file.pub user@192.168.1.110

Now if you try SSHing to the remote server, no password will be required!

Copy files between machines

To copy files between PCs we will use a program called scp. It stands for secure copy.

To copy from localhost to remote server, execute

$ scp path/to/file user@192.168.1.110:path/to/save

To copy from remote server to localhost, just switch the source and destination of the previous command. Execute

$ scp user@192.168.1.110:path/to/copy path/to/save

Synchronize folders between machines

To synchronize folders between PCs we will use rsync.

To sync folder on remote host with files from localhost, execute

$ rsync --archive --compress --partial --progress path/to/folder/ user@remote.com:path/to/folder/

To sync folder on local host with files from remote host, execute

$ rsync --archive --compress --partial --progress user@remote.com:path/to/folder/ path/to/folder/

File transfer with FTP

Sometimes it makes more sense to login to a machine, see what files are present there and then download them. This can be done through sftp,, which stands for secure file transfer protocol.

To use sftp, run

$ sftp user@remote.com

After logging in, you’ll get an interactive shell for traversing paths, uploading and downloading files.

sftp> pwd       # See current working directory on remote
sftp> lpwd      # See current working directory on local

sftp> ls        # List files on current remote directory
sftp> lls       # List files on current local directory

sftp> cd        # Change remote directory
sftp> lcd       # Change local directory

sftp> get remoteFile         # Get remote file
sftp> get remoteFile name    # Get remote file with custom name
sftp> get -r remoteDirectory # Get remote directory

sftp> put localFile          # Upload file to remote
sftp> put -r localDirectory  # Upload folder to remote

Configure local SSH for easier access

Sometimes it is troublesome to write the full user@host.com. It’s especially troublesome when there is no domain configured and you need to enter with an IP like user@92.168.1.110.

We can configure the ssh client to make things easier.

Open ~/.ssh/config. If the file doesn’t exist, create it.

In the file configure your hosts like the following

Host office
    HostName domain.com # or IP
    User john # the user name
    IdentityFile ~/.ssh/key.pub

Now if you can SSH like this

$ ssh office
$ scp office:~/Desktop/file.txt ~/Desktop/file.txt
$ sftp office

Boom! Now you can connect more easily to remote PCs!

SSH Tunneling

Sometimes you may want to forward the port of a client PC to a port of a remote PC. This can be achieved through SSH tunneling.

Serve remote service at client’s localhost (hitting localhost:1313 on client will hit to remote:5000)

$ ssh -L 1313:localhost:5000 root@10.100.101.45
# ssh -L {local_port}:localhost:{remote_port} user@remote.ip

Serve client service at remote’s localhost (hitting localhost:5000 on server will hit to client:1313)

$ ssh -R 5000:localhost:1313 root@10.100.101.45
# ssh -R {remote_port}:localhost:{local_port} user@remote.ip

Mount remote directory locally

This one is my personal favorite. I load the remote directory locally and work on my local machine. Changes made are automatically reflected in the remote directory.

# sshfs must be installed
# $ sudo apt install sshfs
sshfs user@domain:/remote/directory/ /local/directory/