| File/Directory | 
| ls | List Files | 
| cp | Copy Files | 
| mv | Move/Rename Files | 
| rm | Remove Files | 
| ln | Link Files | 
| cd | Change Directory | 
| pwd | Print Current Directory Path | 
| mkdir | Make Directory | 
| rmdir | Remove Directory | 
|  | 
| File Viewers/ Pagers | 
| cat | View Files | 
| less | Page Through Files | 
| head | View File Beginning | 
| tail | View File Ending | 
| nl | Number Lines | 
| od | View Binary Data | 
| xxd | View Binary Data | 
| gv | View Postscript/PDF Files | 
| xdvi | View TeX DVI Files | 
|  | 
| File Creation And Editing | 
| emacs | Text Processor | 
| vi | Text Processor | 
| umask | Set Default File Protections | 
| soffice | Edit Word/Excel/Power Point Documents | 
| abiword | Edit Word Documents | 
| gnumeric | Edit Excel Documents | 
|  | 
| File Properties | 
| stat | Display File Attributes | 
| wc | Count Bytes/Words/Lines | 
| du | Measure Disk Usage | 
| file | Identify File Types | 
| touch | Change File Timestamps | 
| chown | Change File Owner | 
| chgrp | Change File Group | 
| chmod | Change File Protections | 
| chattr | Change Advanced File Attributes | 
| lsattr | List Advanced File Attributes | 
|  | 
| File Location | 
| find | Locate Files | 
| slocate | Locate Files Via Index | 
| which | Locate Commands | 
| whereis | Locate Standard Files | 
|  | 
| File Text Manipulation | 
| grep | Search Text For Matching Lines | 
| cut | Extract Columns | 
| paste | Append Columns | 
| tr | Translate Characters | 
| sort | Sort Lines | 
| uniq | Locate Identical Lines | 
| tee | Copy Stdin To A File And Stdout Simultaneously | 
|  | 
| File Compression | 
| gzip | Gnu Zip | 
| compress | Compression Unix Style | 
| bzip2 | Compression | 
| zip | Windows/Dos Style | 
|  | 
| File Comparison | 
| diff | Compare Files Line By Line | 
| comm | Compare Sorted Files | 
| cmp | Compare Files Byte By Byte | 
| md5sum | Compute Checksums | 
|  | 
| Disks And Filesystems | 
| df | Show Free Disk Space | 
| mount | Make A Disk Accessible | 
| fsck | Check A Disk For Errors | 
| sync | Flush Disk Caches | 
|  | 
| Backups And Remote Storage | 
| mt | Control A Tape Drive | 
| dump | Back Up A Disk | 
| restore | Restore A Dump | 
| tar | Read And Write Tape Archives | 
| cdrecord | Burn A CD | 
| rsync | Mirror A Set Of Files | 
|  | 
| Printing | 
| lpr | Print Files | 
| lpq | View Print Queue | 
| lprm | Remove Print Jobs | 
|  | 
| Spelling Operations | 
| look | Look Up Spelling | 
| aspell | Check Spelling Interactively | 
| spell | Check Spelling In Batch | 
|  | 
| Processes | 
| ps | List All Processes | 
| w | List Users' Processes | 
| uptime | View The System Load And Up Time | 
| top | Monitor Processes | 
| xload | Monitor System Load | 
| free | Display Free Memory | 
| kill | Terminate Processes | 
| nice | Set Process Priorities | 
| renice | Change Process Priorities | 
|  | 
| Scheduling Jobs | 
| sleep | Wait For Some Time | 
| watch | Run Programs At Set Intervals | 
| at | Schedule A Job | 
| crontab | Schedule Repeated Jobs | 
|  | 
| Hosts | 
| uname | Print System Information | 
| hostname | Print System'S Hostname | 
| ifconfig | Set/Display Network Information | 
| host | Look Up DNS | 
| whois | Look Up Domain Registrants | 
| ping | Check If Host Is Reachable | 
| traceroute | View Network Path To A Host | 
|  | 
| Networking | 
| ssh | Securely Log Into Remote Hosts | 
| telnet | Log Into Remote Hosts | 
| scp | Securely Copy Files Between Hosts | 
| sftp | Securely Copy Files Between Hosts | 
| ftp | Copy Files Between Hosts | 
| evolution | GUI Email Client | 
| mutt | Text-Based Email Client | 
| mail | Minimal Email Client | 
| mozilla | Web Browser | 
| lynx | Text-Only Web Browser | 
| wget | Retrieve Web Pages To Disk | 
| slrn | Read Usenet News | 
| gaim | Instant Messaging/IRC | 
| talk | Linux/Unix Chat | 
| write | Send Messages To A Terminal | 
| mesg | Prohibit Talk/Write | 
|  | 
| Audio And Video | 
| grip | Play CDs And Rip MP3 | 
| xmms | Play Audio Files | 
| cdparanoia | Rip Audio | 
| audacity | Edit Audio | 
| xcdroast | Burn CDs |