Beyond the essentials.
WHAT xargs DOES
Builds command lines from input.
WHERE IT HELPS
Acting on the results of find, when the list is too long for a wildcard.
WHAT WATCH DOES
Runs a command repeatedly, showing the output.
WHERE THAT HELPS
Observing a queue draining, or a count changing.
WHAT lsof DOES
Lists open files, including network connections.
WHERE IT HELPS
Finding what is using a port, or holding a deleted file.
WHAT strace DOES
Shows the system calls a process makes.
WHERE IT HELPS
Finding which file a program is failing to open.
WHY THAT IS POWERFUL
It answers questions the application's own errors do not.
WHAT ncdu PROVIDES
Interactive disk usage, navigable.
WHY IT BEATS du
You can walk into the largest directory rather than rerunning commands.
WHAT jq DOES
Queries and formats structured data.
WHERE IT HELPS
Reading output from interfaces and configuration.
WHAT rsync AND tmux ALREADY COVERED DESERVE
Being used by default, not occasionally.
WHAT TO INSTALL ON ANY SERVER YOU MANAGE
The handful of tools you rely on.
WHY
Diagnosing without them takes far longer.
WHAT TO BE CAREFUL ABOUT
Installing unnecessary software on a hardened machine.
