A fast drop-in replacement for matlab's system command.

Ever need to run a shell command or external process from matlab code? Using matlab's built in system command can be extremely slow, causing severe overhead if you're calling it many times. jsystem is a drop-in replacement for system which is both much faster and also has some extra convenience features.

• Run any shell command:

  >> [res, out] = jsystem('ls -R')
  res =
       0
  out =
       LICENSE.md
       README.md
       src
  
       ./src:
       jsystem.m
  

• Use shell built-ins, pipes and redirects:

  >> [res, out] = jsystem('echo "YES" && ls -al | grep src > /dev/null')
  res =
       0
  out =
       YES
  

• Specify your own custom shell to use:

  >> [res, out] = jsystem('echo "My shell is $SHELL"', '/usr/local/bin/zsh')
  res =
       0
  out =
       My shell is /usr/local/bin/zsh
  

• Execute a program directly, without a shell (even faster, since there's no shell startup overhead)

  >> [res, out] = jsystem('/usr/bin/du -h ./src', 'noshell')
  res =
       0
  out =
       4.0K   ./src
  

Run the included benchmarks in test/jsystem_benchmak.m to get an indication of the speedup you can expect to see when using jsystem. Here's a representative result (on my machine - late 2012 macbook pro).

• jsystem vs matlab's built-in system:

  Benchmark #1 - Command: "echo OK > /dev/null", 50 iterations
  system: 17.000 [ms] average
  jsystem: 3.400 [ms] average

• jsystem with and without a shell

  Benchmark #2 - Command: "/bin/ls -al", 50 iterations
  jsystem: 3.600 [ms] average
  jsystem (noshell): 2.600 [ms] average

PRs would be greatly appreciated.

MIT.