Figure 3

Usual compile:
     cc -o checkfor checkfor.c
     
Sample output:
     
  myaccnt@this.machine.com
      myaccnt@that.machine.com
          myaccnt@other.machine.com  End of forwarding chain.
      newacct@that.machine.com
          myaccnt@this.machine.com  Duplicate user/hostname combination!
     
  Finished. 
     
     
Command line invocation:
     
  this.machine.com:/home/myaccnt> checkfor myaccnt@this.machine.com
     
     
Standard input invocation:
     
  this.machine.com:/home/myaccnt> cat userdata | checkfor -s
     
     
Contents of userdata:
  myaccnt this.machine.com
  othracct that.machine.com
     

