| Abbreviation | Definition |
|---|---|
| SIGURG | signal: urgent I/O condition |
| SIGUSR1 | signal: user-defined signal 1 |
| SIGUSR2 | signal: user-defined signal 2 |
| SIGWINCH | signal: window (size) changed |
| stty | Set TeleTYpewriter |
| stty | set tty |
| su | SuperUser |
| sudo | Substitute User DO |
| sync | SYNChronize |
| sz | send Z-modem |
| tar | tape archive(r) |
| tar | Tape ARchiver |
| tclsh | TCL (Tool Command Language) SHell |
| tclsh | Tcl shell |
| tcsh | Tenex C shell |
| tee | T pipe fitting (plumbing device) |
| telnet | TErminal over NETwork |
| tex | tau epsilon chi (greek letters) |
| tr | translate |
| troff | typesetter roff |