Editing AmigaDOS (section)

===Protection bits===
Protection bits are flags that files, links and directories have in the filesystem. To change them one can either use the command '''Protect''', or use the '''Information''' entry from the '''Icons''' menu in Workbench on selected files. AmigaDOS supports the following set of protection bits (abbreviated as HSPARWED):
*H = Hold (reentrant commands with the P-bit set will automatically become resident on first execution. Requires E, P and R bits set to work. Does ''not'' mean "Hide". See below.)
*S = Script (Batch file. Requires E and R bits set to work.) If this protection bit is set on, then AmigaDOS is able to recognize and automatically run a script by simply invoking its name. Without S bit scripts can still be launched using the <syntaxhighlight lang="doscon" inline>Execute</syntaxhighlight> command.
*P = Pure (indicates reentrant commands that can be made resident in RAM and then no longer need to be loaded any time from [[flash drives]], [[hard disks]] or any other media device. Requires E and R bits set to work.)
*A = Archive (Archived bit, used by various backup programs to indicate that a file has been backed up)
*R = Read (Permission to read the file, link or content of directory)
*W = Write (Permission to write the file, link or inside a directory)
*E = Execute (Permission to execute the file or enter the directory. All commands need this bit set, or they won't run. Requires R bit set to work.)
*D = Delete (Permission to delete the file, link or directory)

The H-bit has often been misunderstood to mean "Hide". In [[Smart File System]] (SFS) files and directories with H-bit set are hidden from the system. It is still possible access hidden files but they don't appear in any directory listings.

Demonstration of H-bit in action:
<syntaxhighlight lang="doscon">
AmigaPrompt> which list
Workbench:C/List
AmigaPrompt> list workbench:c/list
Directory "workbench:c" on Thursday 30-Oct-08
list                              6464 --p-rwed 25-Feb-02 22:30:00
1 file - 14 blocks used
AmigaPrompt> which list
Workbench:C/List
AmigaPrompt> protect workbench:c/list +h
AmigaPrompt> which list
Workbench:C/List
AmigaPrompt> list workbench:c/list
Directory "workbench:c" on Thursday 30-Oct-08
list                              6464 h-p-rwed 25-Feb-02 22:30:00
1 file - 14 blocks used
AmigaPrompt> which list
RES list
</syntaxhighlight>

:Notice how the '''list''' command becomes resident after execution when the H-bit is set.