fs

The fs module provides file system operations: reading, writing, and managing files and directories.

import fs

Module functions

fs.read(path)

Reads the entire contents of a file and returns it as a string.

var string content = fs.read("data.txt")

fs.write(path, content)

Writes a string to a file, creating it if it does not exist and overwriting it if it does.

fs.write("output.txt", "Hello, World!")

fs.open(path, mode)

Opens a file and returns a file object. The mode must be one of:

Mode	Description
"r"	Read
"w"	Write (create/overwrite)
"a"	Append

var File f = fs.open("log.txt", "a")
f.write("new entry\n")
f.close()

See File objects below for the methods available on file objects.

fs.exists(path)

Returns true if the file or directory exists, false otherwise.

if (fs.exists("config.txt")) {
    var string cfg = fs.read("config.txt")
}

fs.remove(path)

Deletes a file. Throws an error if the file does not exist.

fs.remove("temp.txt")

fs.mkdir(path)

Creates a directory. Pass true as the second argument to create parent directories and ignore existing ones:

fs.mkdir("output")
fs.mkdir("a/b/c", true)    // creates a, a/b, and a/b/c

File objects

File objects are returned by fs.open(). They have these methods:

Method	Description
.read()	Read all remaining content as a string
.readline()	Read the next line (without newline)
.readlines()	Read all lines as a list of strings
.write(str)	Write a string to the file
.close()	Close the file

Reading line by line

import fs
import console

function main() {
    var File f = fs.open("data.txt", "r")
    var list lines = f.readlines()
    f.close()

    for line in lines {
        console.println(line)
    }
}

Using with for automatic cleanup

The with statement calls .close() automatically when the block exits:

import fs
import console

function main() {
    with fs.open("data.txt", "r") as f {
        var string content = f.read()
        console.println(content)
    }
}

Full example

import console
import fs

function main() {
    // write a file
    fs.write("greeting.txt", "Hello from CColon!")

    // read it back
    var string content = fs.read("greeting.txt")
    console.println(content)

    // append to it
    with fs.open("greeting.txt", "a") as f {
        f.write("\nGoodbye!")
    }

    // read updated content
    console.println(fs.read("greeting.txt"))

    // clean up
    fs.remove("greeting.txt")
}