Writing linux commands

sTeam includes a number of tools namely steam-shell, debug, edit, import and export from git. These tools are only accessible from the tools folder in the sTeam installation. My task is to make a steam command for linux so that all these tools can be accessible from anywhere just like any other linux application.

Problem: https://github.com/societyserver/sTeam/issues/126

The command structure decided is that we have a global sTeam command and sub commands for each of the tools. This structure can be though of as similar to the structure of the git command. The central git command has many sub commands like branch, checkout, reset, merge, etc. I started with making a pike executable and then changing the installation files to copy this executable to /usr/bin. Now this pike executable becomes accessible from anywhere in the system and acts like a linux command.

https://github.com/societyserver/sTeam/pull/127

I wrote the main function to accept the command line arguments and passed them to a function named resolveParam. In this function I am using an if-else structure to segregate the different sub commands. For shell and debug I started a child process to execute the file for these tools present in /usr/local/lib/steam/tools. The following code snippet gives an example.

void resolveParam(int argc,array(string) argv)
{
if(argv[1]=="shell")
{
array command =({"/usr/local/lib/steam/tools/steam-shell.pike"});
object shell = Process.create_process(command, (["stdin":Stdio.stdin,"stdout":Stdio.stdout,"stderr":Stdio.stderr]));
shell->wait();
}
}

I had some problem when I had to accept more arguments than just the sub command. Foe example the edit command works as ./edit <filename1> <filename2> <filename3>… Using the global command it becomes steam edit <filename1> <filename2> <filename3>… I had to pass all the rest of the arguments to the edit scripts. I had to add them in the command array. The first solution would be to loop through the arguments array and add them all, however pike has a very easy and elegant way of doing it in one sentence.

array command = ({"/usr/local/lib/steam/tools/edit.pike"})+argv[2..];

This gets our global command up and running. Rest of the time I spend on resolving merge conflicts while merging all my previous Pull Requests.

https://github.com/Siddhant085/sTeam/tree/gsoc2016

linux command
output showing the use of steam command