Python: Can someone explain this code for me step by step?

Question

I came across this code when searching for a solution. Unfortunately my rep wasn't high enough to comment so I have started a question for help.

The code below works perfectly and does exactly what I needed it to. Problem I have is aside from the 2 obvious bits def function and call function, I am not sure what it is doing. It seems to add like a "\n" newline to the copied string, as when I paste it it does a new line so I want to strip that out. Thanks in advance.

#import subprocess - ok
import subprocess
#define a function called copy2clip which takes 1 argument, txt.
def copy2clip(txt):

    #Call CMD and echo (txt) to the clip program (which is not a python program)
    cmd='echo '+txt.strip()+'|clip'

    #Check that the CMD program ran ok
    return subprocess.check_call(cmd, shell=True)

#call our function and pass it this string....
copy2clip('now this is on my clipboard')

The code is rather dumb, actually; there are better ways to achive what that code does. — Martijn Pieters, Apr 04 '14 at 16:48
(Be very careful using this... if you pass unsanitized user input to `copy2clip()` the user can execute arbitrary code.) — Wooble, Apr 04 '14 at 16:50
This is a valid question, the OP has shown us the effort they've put in to describing their problem, he explained what it is its doing and has a clear question. It's a basic question, but it's still a valid one. — TankorSmash, Apr 04 '14 at 16:52
Hey! I wrote that code! It is [here](http://stackoverflow.com/a/20577725/298607) — dawg, Apr 04 '14 at 17:13
This question appears to be off-topic because it should be on http://codereview.stackexchange.com/. — JasonMArcher, Apr 04 '14 at 18:07

score 2 · Accepted Answer · answered Apr 04 '14 at 16:49

2

My guess is that there is an program called clip that reads the standard input and copies that text into the clipboard.

The rest of the program is easy: it calls the shell with the command:

echo whatever | clip

being whatever the text to be copied to the clipboard. echo copies the text to the standard input of clip and that's all!

But note that this is a terrible way of doing things! Imaging somebody manages to insert the following text into your clipboard: bye ; rm -rf /; echo haha...

answered Apr 04 '14 at 16:49

rodrigo

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Ahh ok, so this is firing up a CMD prompt in the background then it echos my text and pipes to clip and clip is something windows recognises and is nothing to do with python?? – gazeranco Apr 04 '14 at 16:57

Python: Can someone explain this code for me step by step?

1 Answers1