To get the output of ls, use stdout=subprocess.PIPE. >>> proc = subprocess.Popen(‘ls’, stdout=subprocess.PIPE) >>> output = proc.stdout.read() >>> print output bar baz foo The command cdrecord –help outputs to stderr, so you need to pipe that indstead. You should also break up the command into a list of tokens as I’ve done below, or the … Read more
The multiprocessing library provides listeners and clients that wrap sockets and allow you to pass arbitrary python objects. Your server could listen to receive python objects: from multiprocessing.connection import Listener address = (‘localhost’, 6000) # family is deduced to be ‘AF_INET’ listener = Listener(address, authkey=b’secret password’) conn = listener.accept() print ‘connection accepted from’, listener.last_accepted while … Read more
In bash you can use set -e and set -o pipefail at the beginning of your file. A subsequent command ./a | ./b | ./c will fail when any of the three scripts fails. The return code will be the return code of the first failed script. Note that pipefail isn’t available in standard sh.
git update-index wants the file names on its command line, not on its standard input. Step 1: cd into the folder you want to assume is unchanged Step 2: You can do either this: git update-index –assume-unchanged $(git ls-files | tr ‘\n’ ‘ ‘) or git ls-files | tr ‘\n’ ‘ ‘ | xargs git … Read more
A regular pipe can only connect two related processes. It is created by a process and will vanish when the last process closes it. A named pipe, also called a FIFO for its behavior, can be used to connect two unrelated processes and exists independently of the processes; meaning it can exist even if no … Read more
This is also the union set operator set([1,2]) | set([2,3]) This will result in set([1, 2, 3])
Because you’re piping into the while loop, a sub-shell is created to run the while loop. Now this child process has its own copy of the environment and can’t pass any variables back to its parent (as in any unix process). Therefore you’ll need to restructure so that you’re not piping into the loop. Alternatively … Read more
Use isatty: #include <stdio.h> #include <io.h> … if (isatty(fileno(stdin))) printf( “stdin is a terminal\n” ); else printf( “stdin is a file or a pipe\n”); (On windows they’re prefixed with underscores: _isatty, _fileno)
As of March 2017 using escaped pipes is much easier: \| See other answers. If you remove the backticks (`), using the | hack works a | r ————|—– `a += x;` | r1 a |= y; | r2 and produces the following output Alternatively, you can replace the backticks (`) with a <code></code> markup … Read more
I would like to add an even simpler way to do this, using the built-in json pipe: <pre>{{data | json}}</pre> This way, the formatting is preserved.