| Original author(s) | AT&T Bell Laboratories |
|---|---|
| Developer(s) | Various open-source and commercial developers |
| Initial release | 3 November 1971 |
| Written in | Plan 9: C |
| Operating system | Unix, Unix-like, Plan 9, Inferno, IBM i |
| Platform | Cross-platform |
| Type | Command |
| License | coreutils: GPLv3 Plan 9: MIT License |
In Unix and Unix-like operating systems, chmod is the command and system call used to change the access permissions and the special mode flags (the setuid, setgid, and sticky flags) of file system objects (files and directories). Collectively these were originally called its modes,[1] and the name chmod was chosen as an abbreviation of change mode.[2]