SAC, the acronym for Seismic Analysis Code, was developed at Lawrence Livermore National Laboratory, University of California, in the early 1980's.
It is a command-driven program generally implemented on many types of UNIX operating systems and has become a standard data manipulation tool in seismology.
Its binary data format is one of the principle data formats used today in storing and manipulating seismological time series data.
There are also utility programs that can be used to view plots or to convert SAC graphics files into other formats such as PostScript.
These files can then be used with other graphics programs such as Adobe Illustrator to construct more complex figures.
One can also interact directly with the UNIX operating system while using SAC, calling system functions or running secondary programs as needed.
Macros (scripts of SAC commands) can be combined with CShell scripts for automating seismic processing.
SAC binary data files can be written and read from fortran
and C programs using input/output routines contained in the SAC library,