GSH(1)

NAME

gsh - BRL-CAD geometry shell for interacting with .g database files

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SYNOPSIS
DESCRIPTION
OPTIONS
EXAMPLES
SEE ALSO
AUTHOR
COPYRIGHT
BUG REPORTS

SYNOPSIS

gsh [options] [model.g] [command [args ...]]

gsh (the BRL-CAD Geometry SHell) is a low level, terminal based environment for interacting with BRL-CAD geometry database (.g) files through the LIBGED command set. Any command understood by LIBGED, the same command library that powers mged(1) and archer(1), may be issued to gsh.

gsh operates in one of several modes depending on its arguments:

With no command arguments, gsh launches an interactive prompt (`g> `) with command history and line editing. If a model.g file is given it is opened first; otherwise a database may be created or opened from the prompt with the opendb command.
With a model.g file followed by one or more command arguments, gsh opens the database, executes the single command, prints its result, and exits. This non-interactive form is convenient for scripting.
When standard input is not a terminal, gsh reads and executes commands from stdin with no prompt, allowing command streams to be piped in.

Long running LIBGED commands that spawn subprocesses are monitored on separate threads so their output is interleaved with the interactive prompt. Unlike mged(1) and archer(1), gsh provides no graphical display window of its own.

OPTIONS

-h, -?, --help: Print a usage message and exit.
-v, --version: Report the BRL-CAD release and component library versions, then exit.
--new-cmds: Use the new (qged style) LIBGED command forms and DbiState based display update logic instead of the traditional command set. Primarily of use for development and testing of the next-generation command behavior.

EXAMPLES

Example 1. Run a single command non-interactively

gsh moss.g tops

Opens the database moss.g, runs the tops command to list the top level (non-referenced) objects, prints the result, and exits without entering the interactive prompt. This form is well suited to shell scripts and makefiles.

Example 2. Pipe a sequence of commands from stdin

printf 'title\nls\nsummary\n' | gsh moss.g

Feeds several LIBGED commands into gsh on standard input. Because stdin is not a terminal, gsh executes each line in turn with no prompt, reporting the database title, an object listing, and a summary of the contents of moss.g.

Example 3. Inspect and modify geometry interactively

gsh
g> opendb sample.g y
g> in box.s rpp 0 10 0 10 0 10
g> r box.r u box.s
g> tops
g> quit

Starts an interactive session, creates a new database, builds an RPP primitive and wraps it in a region, then lists the resulting top level objects. The same LIBGED commands available here are shared with mged(1) and archer(1).