DU (man1p)
du — estimate file space usage
du — estimate file space usage
jobs — display status of jobs in the current session
mailx — process messages
true — return true value
sact — print current SCCS file-editing activity (DEVELOPMENT)
cmp — compare two files
uname — return system name
pathchk — check pathnames
qdel — delete batch jobs
cflow — generate a C-language flowgraph (DEVELOPMENT)