DOKK / manpages / debian 12 / fiu-utils / fiu-run.1.en
fiu-run(1) General Commands Manual fiu-run(1)

fiu-run - a script to launch programs using libfiu

fiu-run [options] program [program arguments]

fiu-run is a script to make it easier to launch programs using libfiu(3). It can enable failure points and start libfiu's remote control capabilities before starting to execute the program, avoiding the need to write a special launcher to inject failures.

It is specially useful when used to inject failures in the POSIX/libc functions, because it does not require any program modifications.

After launching programs with fiu-run, fiu-ctrl(1) can be used to enable and disable their failure points at runtme.

For additional documentation, go to the project's website at

Run the given libfiu remote control command before executing the program (see below for reference).
Use the POSIX libfiu preload library, allows simulate failures in the POSIX and C standard library functions.
Enable remote control over named pipes with the given path as base name, the process id will be appended (defaults to "$TMPDIR/fiu-ctrl", or "/tmp/fiu-ctrl" if "$TMPDIR" is not set). Set to "" to disable remote control over named pipes.
Path where to find the libfiu preload libraries. Defaults to the path where they were installed, so it is usually correct.

Remote control commands are of the form "command param1=value1,param2=value2". Valid commands are:

'enable name=NAME'
Enables the NAME failure point unconditionally.
'enable_random name=NAME,probability=P'
Enables the NAME failure point with a probability of P.

All of the enable* commands can also optionally take failnum and failinfo parameters, analogous to the ones taken by the C functions.

The following will run the fortune(1) program simulating faults in read() with 5% probability (note that the -x parameter is required in this case to enable failure points in the POSIX and libc functions):

fiu-run -x -c "enable_random name=posix/io/rw/read,probability=0.05" fortune

By running it multiple times you will see that sometimes it works, but most of the time you get different errors, resulting from the simulated failures.

libfiu(3), fiu-ctrl(1).

If you want to report bugs, or have any questions or comments, just let me know at For more information about libfiu, you can go to