I am relatively new to the python’s subprocess and os modules. So, I was able to do the process execution like running bc, cat commands with python and putting the data in stdin and taking the result from stdout.
Now I want to first know that a process like cat accepts what flags through python code (If it is possible).
Then I want to execute a particular command with some flags set.
I googled it for both things and it seems that I got the solution for second one but with multiple ways. So, if anyone know how to do these things and do it in some standard kind of way, it would be much appreciated.
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Answer
In the context of processes, those flags are called arguments, hence also the argument vector called argv. Their interpretation is 100% up to the program called. In other words, you have to read the manpages or other documentation for the programs you want to call.
There is one caveat though: If you don’t invoke a program directly but via a shell, that shell is the actual process being started. It then also interprets wildcards. For example, if you run cat with the argument vector ['*'], it will output the content of the file named * if it exists or an error if it doesn’t. If you run /bin/sh with ['-c', 'cat *'], the shell will first resolve * into all entries in the current directory and then pass these as separate arguments to cat.