To run a VIPS function, the first argument should be the name of the function and following arguments should be the function parameters. For example:
example% vips im_invert lena.v lena2.v
To query the VIPS function database, use "-help", then the name of a function or a package. For example:
example% vips -help
"-help flags" for a list of flags available
"-help <package name>" for a list of commands in package
where <package name> is one of:
arithmetic (31 functions)
boolean (8 functions)
colour (24 functions)
... etc
relational (13 functions)
"-help all" for a list of all commands in all packages
"-help <command>" for an explanation of a command
example% vips -help arithmetic
functions available in package "arithmetic":
im_abs - absolute value
im_acostra - acos of image (result in degrees)
... etc
im_stats - many image statistics in one pass
im_tantra - tan of image (angles in degrees)
example% vips -help im_abs
vips: args: in out
where:
in is of type "image"
out is of type "image"
absolute value, from package "arithmetic"
flags: (PIO function) (no coordinate transformation)
example%