rosshell

Two simple nodes that can be used as mediators for shell commands.

Author: André Dietrich & Sebastian Zug
License: BSD
Source: https://gitlab.com/andre-dietrich/rosshell

1. Overview

This package provides the two nodes, that enable to run and interact with different non-ros-programs. rosshell can be used to start a program or any kind of shell-command. If some kind of interaction with the programs is required, use rosshellX to receive and send messages from stdin, stdout, and stderr.

2. Usage

The required commands are always defined as a string:

$ rosrun rosshell rosshell.py "command"

$ rosrun rosshell rosshellX.py "command"

have a look at the examples or at the included launch-files.

3. Examples

3.1 rosshell

This command is just used to generate some random noise …

$ rosrun rosshell rosshell.py "aplay -c 2 -f S16_LE -r 44100 /dev/urandom"

Pipe the results of /dev/random into a text file …

$ rosrun rosshell rosshell.py "cat /dev/random > test.txt"

or the some information about the current directory …

$ rosrun rosshell rosshell.py "ls -Shal > test.txt"

3.2 rosshellX

This node is used if you require some interaction with stdin, stdout, and stderr.

rosshellX is by default subscribed to /rosshellX/stdin and publishes at topic /rosshellX/stdout and /rosshellX/stderr, all of type std_msgs/String.

3.2.1 Some basic calculations

bc is just a simple commandline-calculator

1. open three shells

2. start bc with the following command:

   $ rosrun rosshell rosshellX.py "bc"
   

1. print the the results of bc stdout by running:

   $ rostopic echo /rosshellX/stdout
   

1. and now, send some inputs like:

   $ rostopic pub /rosshellX/stdin std_msgs/String "99*99\n"
   $ rostopic pub /rosshellX/stdin std_msgs/String "sqrt(2.0)\n"
   $ rostopic pub /rosshellX/stdin std_msgs/String "33^3\n"
   $ rostopic pub /rosshellX/stdin std_msgs/String "quit\n"
   

1. to interact a bit with stderr, simply subscribe for:

   $ rostopic echo /rosshellX/stderr
   

and publish some nonsense like

   $ rostopic pub /rosshellX/stdin std_msgs/String "wtf\n"
   

3.2.1 Additional functionality

To get some filesystem-information try:

$ rosrun rosshell rosshellX.py "ls -Shal"

or

```bash $ rosrun rosshell rosshellX.py _command:=”ls -Shal”

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