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 shell mode using the ; modifier, for example: ; cd folder: navigates to folder

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

 

 

The following are some examples for Linux or macOS X (at the time of writing: September 2018):

# Code in Chapter 9\shell.jl: 
cmd = `echo Julia is smart` 
   typeof(cmd) #> Cmd  
   run(cmd) # returns Julia is smart
   run(`date`) #> Sat Jul 14 09:44:50 GMT 2018 
   cmd = `cat file1.txt` 
   run(cmd) # prints the contents of file1.txt...