Micro Focus Studio Enterprise Edition for UNIX > Programming > Data Access > File Handling > File Handling Guide > File Organizations > The Library Command Line Interface > Overview

Overview

Library enables you to group individual files into one file. You also can use Library to group together static source code to create copy libraries. Using Library gives you the following advantages:

Files are not so easily mislaid.
Whole suites of programs and/or sets of data files can be stored in one library file.
Performance is improved.
Once the library file is opened, all the files it contains are readily accessible. You access data files in libraries by the usual OPEN, READ, and CLOSE statements; OPEN and CLOSE become logical operations handled by the run-time system rather than the more time-consuming physical operations.
Access to files in a library is maintained.
When you change directory you can still access files in a library in the original directory because the library catalog remains in memory.
Ease of use on floppy disk systems.
If an application contains a call to a library not currently on the logged-on drive and the library has been built into your program, the system prompts you to insert the .lbr file.

CAUTION:

Files in libraries are read-only; you cannot access them via WRITE or REWRITE. Trying to open such a file using OPEN OUTPUT or OPEN I-O will open a file outside the library, then WRITE or REWRITE will update this file leaving the file in the library unchanged.
Once a library file has been created, files within it can only be updated. It is not possible to extract files from a library file.
As files packaged in library files cannot be extracted, you cannot use the debugging features of Server Express with them.

You invoke Library from the operating system command line; it runs in batch mode. The following sections describe how to invoke Library, how to create a Library batch file and how to access files in libraries.