Open System Services Management and Operations Guide (G06.29+, H06.07+)

Managing OSS Files
Open System Services Management and Operations Guide—527191-005
6-28
Redirecting OSS Standard Files
also written to the terminal display. Data read or written through these files can be
redirected using shell redirection specifications to other processes or to regular (disk)
files. On a UNIX system, the pseudo-TTY feature ptty can be used as a source or
sink for such data redirection; although the OSS environment does not have a pseudo-
TTY feature, OSSTTY can do similar data redirection.
A Guardian process has three standard files, comparable to the OSS files mentioned
above, that normally possess the structure of an EDIT file:
•
STDIN, usually called the IN file in commands entered from a TACL prompt
•
STDOUT, usually called the OUT file in commands entered from a TACL prompt
•
STDERR, usually called the TERM file in commands entered from a TACL prompt
By default, these files are associated with the user’s home terminal (HOMETERM).
However, the command that runs a Guardian process can redirect those files to
Guardian processes or files.
An OSS user normally launches an OSS shell by logging in through Telserv, most
commonly by starting a TACL session and entering the OSH command. That access
method leaves the OSS standard files associated with the user’s terminal but allows no
way for those files to be redirected to Guardian processes or files.
The OSSTTY utility, described in OSSTTY on page C-1, removes that restriction. To an
OSS process, OSSTTY appears to be a set of three terminal devices (one for each
OSS standard file); to a Guardian process or the Guardian file system, the OSS
process appears to be a Guardian file-system object. OSSTTY can be started by an
individual user through the OSH command or directly by an OSS administrator.
OSSTTY can be used to redirect one or more OSS standard files to Guardian EDIT
files or Guardian processes. Figure 6-5 on page 6-29 illustrates use of the OSS shell
when only the OSS standard output and standard error files are redirected, but input is
still accepted from the Telserv terminal that enters the following command; the process
name $ZAAA is assigned by the NonStop operating system when OSSTTY is started:
OSH -osstty / OUT $DATA.OSSLOG.EDITFIL, TERM $VHS /