Seeing Which Version Has Been Retrieved: The what Command

Since SCCS allows you (or others) to retrieve any version in the file history, there is no guarantee that a working copy present in the directory reflects the version you want. The what command scans files for SCCS ID keywords. It also scans binary files for keywords, allowing you to see from which source versions a program was compiled.

$ what program.c program 
program.c:
      program.c 1.1 88/07/05 SMI; 
program: 
     	program.c 1.1 88/07/05 SMI;

In this case, the file contains a working copy of version 1.1.