Running shell commands

To interact with the operating system from within the Julia REPL, there are a few helper functions available as follows:

• pwd(): This function prints the current directory, for example, "d:\\test"

• cd("d:\\test\\week1"): This function helps to navigate to subdirectories

• In the interactive shell, you can also use the shell mode using the ; modifier:

  • ; ls: This prints, for example, file1.txt shell.jl test.txt tosort.txt

  • ; mkdir folder: This makes a directory named folder

  • ; cd folder: This helps to navigate to folder

However, what if you want to run a shell command by the operating system (the OS)? Julia offers an efficient shell integration through the run function, which takes an object of type Cmd that is defined by enclosing a command string in backticks (``):

# Code in Chapter 9\shell.jl:
   cmd = `echo Julia is smart`
typeof(cmd) #> Cmd 
    run(cmd) # returns Julia is smart
    run(`date`) #> Sun Oct 12 09:44:50 GMT 2014
cmd = `cat file1.txt`
run(cmd) ...