Shell

The SHELL command is the interface to the operating system, Unix and VMS:

Format:

SPECTRA> shell

Description:

SPECTRA spawns a subprocess and attaches control to it. An exit (logout) command finishes the sub-process and control is returned to the SPECTRA command line.

Format:

SPECTRA> shell command_string

Description:

The command string is passed to the operating system. It is executed in a subprocess. As a consequence certain commands might not exhibit the expected effect, in particular all those commands which change process specific attributes.

Caution: It is not possible to use symbols inside the command line. Example:

SPECTRA> file = laser.hp
SPECTRA> shell print/que=f41ps1 file wrong!

The last command won't work because VMS sees the string "print/que=f41ps1 file" and not "print/que=f41ps1 laser.ps " which was intended by the user. However, it is possible to tailor a SHELL command string using symbol replacements: The symbols have to be concatenated to a single symbol, which contains the entire command line.

Example:

SPECTRA> file = laser.ps
SPECTRA> com_line = "shell print/que=f41ps1 "file
SPECTRA> com_line

The symbol COM_LINE contains "shell print/que=f41ps1 laser.ps". It is translated at the beginning of the syntax analysis. Then the verb SHELL is recognized and everything else works fine.

e.g.:

SPECTRA> shell dir

SPECTRA> shell mail