| quota | Display disk usage and limits |
| quotacheck | Scan a file system for disk usage |
| quotactl | Set disk quotas |
| ram | ram disk device |
| rcp | Copy files between two machines |
| read | Read a line from standard input |
| readarray | Read from stdin into an array variable |
| readonly | Mark variables/functions as readonly |
| reboot | Reboot the system |
| remsync | Synchronize remote files via email |
| rename | Rename files |
| renice | Alter priority of running processes |
| return | Exit a shell function |
| rev | Reverse lines of a file |
| rm | Remove files |
| rmdir | Remove folders |
| rsync | Remote file copy (Synchronize file trees) |
| scp | Secure copy (remote file copy) |
| screen | Multiplex terminal, run remote shells via ssh |
| sdiff | Merge two files interactively |
| sed | Stream Editor |
| select | Accept keyboard input |
| seq | Print numeric sequences |
| set | Manipulate shell variables and functions |
| sftp | Secure File Transfer Program |
| shift | Shift positional parameters |
| shopt | Shell Options |
| shutdown | Shutdown or restart linux |
| sleep | Delay for a specified time |
| slocate | Find files |
| sort | Sort text files |
| source | Run commands from a file |
| split | Split a file into fixed-size pieces |
| ssh | Secure Shell client (remote login program) |
| strace | Trace system calls and signals |
| su | Substitute user identity |
| sudo | Execute a command as another user |
| sum | Print a checksum for a file |
| suspend | Suspend execution of this shell |
| symlink | Make a new name for a file |
| sync | Synchronize data on disk with memory |
| tail | Output the last part of file |
| tar | Tape Archiver |
| tee | Redirect output to multiple files |
| test | Evaluate a conditional expression |
| time | Measure Program running time |
| times | User and system times |
| top | List processes running on the system |
| touch | Change file timestamps |
| tr | Translate, squeeze, and/or delete characters |
