[Info-vax] Porting logical name applications to Unix

[John E. Malmberg]

JF Mezei wrote:
> Paul Raulerson wrote:
>> The
>> idea of course is to use generic file names in the programs, and  
>> attach them at runtime.
> 
> Ok, what is the best way to achieve this ? VMS has logical names, and
> MVS has DD statements in JCL and their equivalent in TSO.  With Unix, do
> you open "input.dat" and then create a link in the directory called
> "input.dat" which points to the actual file ?

Go look at the source code for similar programs that are open source 
along with reading the various standards.

Unix programs that take options can can use any of the following:

1. Looking for a specially named option file in the login directory.

2. Looking for a specially named option file in a specially named folder 
under the login directory.

3. Looking for a specially named option file in a system directory like 
/etc or a directory under it.

4. Looking for a specially named option file in a system directory 
somewhere else.

5. Looking for option files named by one or more environment variables.

6. Looking for options in the command line.

Generally the command line options have the highest precedence, followed 
by environment variables, followed by the login directory, and then the 
system directories.

Most programs read from standard input and write to standard output, but 
some will take options to read and write to files.

-John
wb8tyw at qsl.network
Personal Opinion Only