| Command | Meaning |
|---|---|
| df | space left on the system |
| du | kilobytes used by a directory |
| gzip | reduces the size |
| gunzip | expands a file |
| zcat | read gzipped files |
| file | classifies the file according to its type |
| diff | compares the content of two files |
| find | search through the directories |
| history | keeps an ordered list of all the commands |
| ^R | recursive search |
| ps | list current processes |
| bc | calculator |