Annotated commands and utilities, persisted to help me remember them.
top # then press "1" to get CPU% per core
ps faxwu # subprocess tree, add more w's for more info
ps axl
lsof -p <pid> # list open files, look for pipes
strace -p <pid> # look at the syscalls for this process
strace -f <command> # follow a command - everything and everything it forks
free -h # human readable
nix-shell <command> --option fallback true --option substitute false # if hydra is down