HP 3000 Manuals HP 3000 Manuals
Redirecting Command Input and Output
Redirection is accomplished with the use of the following simple
redirection indicators <, > or >>, followed by a file name, or
backreference to a file equation.
The < sign indicates that CI input comes from the specified file. The >
sign indicates that CI output goes to the specified file. The >> sign
also indicates that CI output goes to the specified file; however, output
is appended to the file (if it exists) so existing data is not
overwritten.
Redirection is supported for single files only; therefore, wildcarding on
the file name is meaningless and returns an error.
The following are examples of CIOR.
Redirecting Command Input
To redirect command input you would enter:
command < infile
Command can be any MPE/iX command except for the following:
* CALC
* COMMENT
* ELSEIF
* IF
* REMOTE
* SETVAR
* SETJCW
* TELL
* TELLOP
* WARN
* WHILE
and infile is the file that contains the input to that command.
For example:
editor < edinput
This invokes the EDITOR and instructs it to read data from the file
edinput. The data is used by EDITOR as if it was being typed as input at
the terminal.
Redirecting Command Output
To redirect command output you would enter:
command > outfile
Once again, command is as described above and outfile is the file which
contains the output of the command.
For example:
showme > userfile
This invokes the showme command and instructs it to write its output to a
file called userfile.
Redirecting Both Command Input and Output
CIOR enables you to redirect both input and output at the same time.
To accomplish this, you would enter:
command <infile >outfile
For example,
editor <edinput >$null
This invokes EDITOR, instructs it to read input from file edinput and to
write output to $NULL. Output from EDITOR for includes the banner, the
prompt and all other EDITOR output.
Redirecting I/O with a File Backreference
Backreferencing a file equation with CIOR is both simple and useful. To
accomplish it you enter:
file formaldesig1;parm...;parm...
file formaldesig2;parm...;parm...
command <*formaldesig1 >*formaldesig2
[REV BEG]
NOTE The FILE command accepts the MPE escape syntax, allowing you to
reference HFS (hierarchical file system) file names, but only on
the right hand side of the equation. Refer to MPE/iX Commands
Reference Manual (32650-90003) for more information about using
the FILE command with HFS names.
[REV END]
You may backreference both input and output to different file equations
or either input or output to a single file equation.
For example:
file sourclst;save;rec=-80,,f,ascii
listfile S@, qualify > *sourclst
This example first establishes file equations to override redirection
file defaults. It then issues a listfile command and directs its output
to the file sourclst. The ;save option in the file equation keeps the
file in the permanent domain. Without ;save the file sourclst would stay
in the default (temporary) file domain.
Redirection file defaults are discussed in a later section in this
chapter.
[REV BEG]
NOTE The LISTFILE command accepts the MPE escape syntax, allowing you to
reference HFS (hierarchical file system) file names, but only on
the right hand side of the equation. Refer to MPE/iX Commands
Reference Manual (32650-90003) for more information about using
the LISTFILE command with HFS names.
[REV END]
Appending Redirected Command Output
When the > sign is used, command output is redirected to the specified
file and it begins writing output at the beginning of the file. When the
>> sign is used, command output is redirected to the specified file, but
it is appended to the file, so information already contained in the file
is not overwritten. If >> is used and the file does not exist, it will
be created.
The append form of output redirection (>> sign) is useful when the output
is a logging message or has a logging function, or when the user is
creating a file with several commands. If your goal is to create a file
containing only the output of the current command you should use the >
sign and not the >> sign.
[REV BEG]
Redirection supports HFS (hierarchical file system) names. ECHO Hi
There! >> ./somefile appends to the file ./somefile[REV END]
To append redirected output enter:
command >>outfile
For example:
echo text file1 > edinput
echo find "patt1" >> edinput
echo delete >> edinput
echo keep >> edinput
echo exit >> edinput
The first line in this example produces the temporary file edinput. The
next four lines append edit commands to this file. The result is a file
of commands that might be read by the EDITOR subsystem with CIOR in the
following command:
editor <edinput >$null
This command invokes the EDITOR and causes it to read the commands
previously written to the file edinput. Command output, in this case, is
redirected to $NULL.
Printing the edinput file shows the commands that the EDITOR would read
as input:
print edinput
text file1
find "patt1"
delete
keep
exit
Redirecting Output to a Device File
To redirect output to a device file (such as a printer), simply
backreference a file equation for the device as follows:
file formaldesig;dev=...
command >*formaldesig
For example:
file lp602;dev=epoc;env=lp602.hpenv.sys
listfile @.@.myaccount,-2 > *lp602
This example would send a listing of all access control definition (ACD)
data to the printer defined by the file equation with formal file
designator lp602.
The Append Option with Device Files.
The redirection append option (use of the >> sign) produces a different
result with device files than with disk files. For example, you could
enter:
file lp602;dev=epoc;env=lp602.hpenv.sys
listfile @.@.myaccount,-2 > *lp602
listfile @.@.myaccount,4 >> *lp602
Both listfile commands are directed to a printer in this example. When
the first listfile command finishes, its spoolfile is closed and made
ready for printing. Once this happens to a spoolfile it cannot be
reopened. For this reason, the second listfile command cannot append to
the first file even though the >> sign has been used. The second
listfile command simply writes another spoolfile.