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FLX(1) General Commands Manual FLX(1)


flx - access and modify RSTS disk image files




flx is a program to access and modify the contents of disks or disk images for the RSTS operating system running on PDP-11 computers.

When COMMAND is given, flx will execute the command and terminate. Without COMMAND it will enter interactive mode where multiple commands can be entered with the exit command to quit. As a special case, if the command is disk, it will be executed (selecting the named disk file) and interactive mode will be entered.

The RSTS disk image file used for a command is selected in the following order in decreasing priority:

  • The -disk switch to the command
  • By a previous disk command
  • By the contents of the RSTSDISK environment variable
  • As "rsts.dsk" in the current directory


Specify the path to the disk image file to be used instead of the default "rsts.dsk" when it is not overridden by the disk command or the -disk switch to a command.


The original documentation indicates that it refuses to run on big endian architectures and may not work correctly on 64-bit architectures.


The full documentation including all commands can be found in /usr/share/doc/simtools/flx.pdf.gz
2017-10-15 simtools