Look before you touch
On a server you'll constantly peek at config files and logs, and hunt for files whose location you don't know. globs like *.log match many names at once, and find searches whole trees.
Peek, count, search
cat /etc/hostname head -n 3 /etc/passwd tail -n 2 /var/log/nginx/access.log wc -l /var/log/nginx/access.log file /etc/passwd /usr/bin/ls ls /etc/*.conf /etc/host* find /var/www -name "*.html" find ~ -type d -name "*cafe*"