# Process manager
htop

# process info (sorted by memory, works almost everywhere)
ps aux --sort=-rss

sudo journalctl -u <service> -xe

# Follow journal with colors (install ccze seperately
journalctl --follow | ccze

# View disk usage (updates every 5 seconds)
watch -n 5 df -h

# View memory usage (updates every 5 seconds)
watch -n 5 free -m

# View kernel messages
dmesg --follow<br><br>

• wondering if it reads the config file or listening on the socket you’re expecting: lsof
• is my program just sitting there: strace
• I wonder how the C++ mangling went: strings
• Did I link that correctly: ldd
• so was that file saved in UTF-8 or latin: od
• wait, is it trying to use the proxy or not: tcpdump
• size of memory segments and swap usage: pmap
• and others like top/ntop/iotop, digging around in /proc/$mypid, ps for showing the env and everything, dtrace and gdb for super detailled tracing