The /etc/uucp/Sysfiles file lets you assign different files to be used by uucp and cu as Systems, Devices, and Dialers files. For more information about cu, see the cu (1C) man page. You can use Sysfiles for the following:
Different Systems files so that requests for login services can be made to different addresses than uucp services.
Different Dialers files so that you can assign different handshaking for cu and uucp.
Multiple Systems, Dialers, and Devices files. The Systems file in particular can become large, making the file more convenient to split into several smaller files.
service=w systems=x:x dialers=y:y devices=z:z
Represents uucico, cu, or both commands separated by a colon
Represents one or more files to be used as the Systems file, with each file name separated by a colon and read in the order that it is presented
Represents one or more files to be used as the Dialers file
Represents one or more files to be used as the Devices file
Each file name is assumed to be relative to the /etc/uucp directory unless a full path is given.
service=uucico:cu systems=Systems :Local_Systems
When this entry is in /etc/uucp/Sysfiles, both uucico and cu first check in the standard /etc/uucp/Systems. If the system being called does not have an entry in that file, or if the entries in the file fail, then both commands check /etc/uucp/Local_Systems.
As specified in the previous entry, cu and uucico share the Dialers and Devices files.
When different Systems files are defined for uucico and cu services, your machine stores two different lists of Systems. You can print the uucico list by using the uuname command or the cu list by using the uuname –C command. The following is another example of the file, which shows that the alternate files are consulted first and the default files are consulted if necessary:
service=uucico systems=Systems.cico:Systems dialers=Dialers.cico:Dialers \ devices=Devices.cico:Devices service=cu systems=Systems.cu:Systems \ dialers=Dialers.cu:Dialers \ devices=Devices.cu:Devices