Updating /etc/magic

The UNIX command file(1) determines the type of a file by examining its contents. By modifying the file /etc/magic, which records characteristics of files that file(1) recognizes, file(1) can be used to identify QOF files and QOF files that are saved states.

The sys component postinstall script attempts to modify this file, adding the following lines to the end:

     0       string      QOF             Quintus Prolog Object File,
     >10     short       x               Ver %d
     >8      short       x               Rev %d
     >12     long        0x04030201      (byte-swapped)
     256     string      QOF             Quintus Prolog Saved-state,
     >266    short       x               Ver %d
     >264    short       x               Rev %d
     >268    long        0x04030201      (byte-swapped)
     

If /etc/magic has been updated, and the file camerton.qof is a QOF file that has been built using Quintus Prolog Release 3.5, you should see:

     % file camerton.qof
     camerton.qof: Quintus Prolog Object File; Ver 1 Rev 71
     

If you do not install the sys component on your system then the same effect can be achieved by creating your own copy of the system's /etc/magic file and adding the above lines to it.

Your version of /etc/magic can then be used with the -m option to file(1) to recognize QOF files. If you have made your own copy of /etc/magic in ~/mymagic and modified that copy as suggested, you can type:

     % file -m ~/mymagic camerton.qof
     camerton.qof: Quintus Prolog Object File; Ver 1 Rev 71