Working on a remote computer

Our computers are powerful, but not always enough for the task at hand.

They do not always work 24/7.

Some servers (cloud or others) are better equipped for storage and computation ⇒ it would be interesting to be able to use these servers to process our data.

These servers are not always physically accessible.

Use of SSH (secure shell) protocol and associated tools.

Connect from a local workstation to a remote machine and work on it or on a cluster of machines
⇒ Shared resources and/or shared time.

Often, only the command line is available
⇒ our terminal is a window on the remote machine
⇒ use of the command line
⇒ use a text editor in console mode (Nano, Emacs, Vim, …​).

Be able to run commands on a remote machine
→ connect to it and run commands.

Be able to disconnect from the remote machine without interrupting work in progress
→ launch a program in the background or use a virtual terminal.

Schedule jobs for certain times of the day
→ use scheduling utilities.

Use of SSH protocol (ssh ou PuTTY)

$> ssh prince.charming@remote-computer.far.far.away
Enter password for prince.charming@remote-computer.far.far.away:
remote-computer:~$
...
...
^Ctrl+D
$>

Encrypted connection

login via password or certificate.

Use tmux or screen commands on the remote machine.

Create multiple virtual terminals within a single terminal (multiplexing).

Useful for commands providing output that you want to be able to browse later without having to save it.

Allows you to disconnect while the process continues.

Use of the cron service on the remote machine
→ through the crontab command.

Allows you to schedule recurring events.

$> crontab -l
# m h  dom mon dow   command
0 3 * * * /usr/local/bin/crunch.sh >> /var/log/crunch.log 2>&1
$>

crontab -e to edit planning

crontab -l to visualize planning