### 3 System Requirements and Getting Started

catremote is available for all the versions of Unix supported by Starlink: Compaq Alpha/Tru64, Sun/Solaris and PC/Linux. It may well work on other versions of Unix, but is not supported on them.

catremote is a simple Perl script (see, for example, SUN/193[1]) and hence Perl must be available on your system before you can run it. It was developed using Perl 5. On Starlink systems catremote is located in file:

/star/bin/cursa/catremote

On non-Starlink systems a release of catremote includes a copy of the script and this document. On such systems you may need to edit the first line of catremote to pick up Perl from wherever on your system it is located.

The purpose of catremote is to query remote catalogues via the Internet. The ACL format that it uses for this purpose itself uses the World Wide Web Hyper-Text Transfer Protocol (HTTP). Consequently, catremote will only run on computers connected to the Internet and configured to run Web browsers.

Though catremote assembles the queries and writes the resulting tables of selected objects, it runs a separate utility program to submit the query to the server and retrieve the results. A number of alternative utility programs can be used for this purpose, including the C program geturl which is supplied with catremote and is the default on Starlink systems. The various alternatives are described in Section 9. The Unix environment variable CATREM_URLREADER (below) specifies which utility program is to be used and must be set before catremote is invoked.