10 command-line tools to install on a new VPS

A freshly delivered VPS comes with only the base distribution packages. Before putting anything online, it's worth installing a handful of tools that save time every day: tools to see what's consuming CPU, what's filling the disk, what's happening on the network. On Ubuntu and Debian they all install with apt, in less than five minutes.

The table

Tool	What it does	Installation	Usage example
htop	Interactive process monitor, alternative to top	sudo apt install htop	htop -u www-data
ncdu	Analyzes disk usage folder by folder	sudo apt install ncdu	ncdu /var/www
tmux	Persistent terminal sessions, survive SSH disconnections	sudo apt install tmux	tmux new -s backup
fail2ban-client	Check fail2ban status and active jails	sudo apt install fail2ban	fail2ban-client status sshd
dig	Query DNS, useful for verifying propagations and records	sudo apt install dnsutils	dig +short example.it MX
mtr	Combines ping and traceroute into a continuous report	sudo apt install mtr	mtr -rwc 10 8.8.8.8
tldr	Practical examples of commands, faster than man	sudo apt install tldr	tldr tar
fzf	Fuzzy search on file lists, commands, history	sudo apt install fzf	find /etc -type f | fzf
rsync	Copy and sync files, used for backups and migrations	sudo apt install rsync	rsync -avz --delete /var/www/ user@host:/backup/
ripgrep (rg)	Search text in files, much faster than grep on large trees	sudo apt install ripgrep	rg "ERROR" /var/log/nginx/

Two notes that save an hour

ripgrep via apt only works from Ubuntu 18.10 onwards or on Debian stable: if you're using Debian stable, ripgrep is officially maintained by Debian, although the version may be older than the deb package available in the previous step. On older Ubuntu versions the package is not available—ripgrep is not in Ubuntu 18.04 because it requires Ubuntu 18.10 or newer. In that case download the .deb file from the releases page on GitHub and install it with dpkg -i.

For tldr: after installation via apt, the page cache needs to be downloaded manually with tldr -u, otherwise the commands appear empty on first use.

A sensible order

On a new VPS the logical order is: tmux first (before anything else, because the SSH session can drop during other installations), then htop and ncdu to understand what's already on the machine, then fail2ban if the SSH port is exposed to the internet, finally dig/mtr when you're configuring DNS or need to understand why latency to a client is high. fzf, tldr and ripgrep are daily conveniences; install them when you have a minute.

None of these tools require a server restart or changes to critical configuration files: they're user packages, removed with sudo apt remove <package> without leaving traces.