| Abbreviation | Definition |
|---|---|
| tsh | trusted shell |
| tsort | Topological SORT |
| ULB | Usr Local Bin |
| ulimit | User's LIMIT |
| uniq | unique |
| UTS | Unix Time Sharing |
| vi | visual |
| wall | write all |
| wish | windowing shell |
| WML | Website MetaLanguage |
| xargs | extended arguments |
| xdpr | X dump print |
| xfd | X Font Display |
| xmkmf | X make makefile |
| xrdb | X resource database |
| xwd | X window dump |
| xwud | X window un-dump |
| ZCVF | Zip Compress Volume File |
| ZIP | ZIv Packer |