<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_context(line, pos):
 """ computes start and end position of substring of line that is the command string under given position """

        commands = split_commandline(line) + ['']
        i = 0
        start = 0
        end = len(commands[i])
        while pos > end:
            i += 1
            start = end + 1
            end += 1 + len(commands[i])
        return start, end