diff --git a/df/main.go b/df/main.go
new file mode 100644
index 0000000..effe3ab
--- /dev/null
+++ b/df/main.go
@@ -0,0 +1,53 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"jsh"
+	"strings"
+)
+
+// Converts raw output of "ps" into a slice of Filesystem objects
+func DfOutputToFilesystems(out string) *[]jsh.Filesystem {
+	filesystems := []jsh.Filesystem{}
+	lines := strings.Split(out, "\n")
+	header, fses := lines[0], lines[1:]
+	numFields := len(strings.Fields(header))
+
+	for _, fs := range fses {
+		allFields := jsh.FieldsN(fs, numFields)
+		if len(allFields) != 0 {
+			fields := append(allFields[0:4], allFields[5])
+			p, err := jsh.NewFilesystem(fields)
+			if err == nil {
+				filesystems = append(filesystems, *p)
+			}
+		}
+	}
+	return &filesystems
+}
+
+func runJsonMode() {
+	dfOut := string(*jsh.FallbackWithArgs("df", []string{"-B1"}))
+	filesystemsPtr := DfOutputToFilesystems(dfOut)
+	frame := jsh.JshFrame{*filesystemsPtr, []string{}}
+
+	queue := make(chan *jsh.JshFrame)
+	done := make(chan bool)
+	go jsh.OutputFrames(queue, done)
+	queue <- &frame
+	close(queue)
+	<-done
+}
+
+func main() {
+	// Parse for JSON flag.
+	jsonModePtr := flag.Bool("json", false, "a bool")
+	flag.Parse()
+
+	if !*jsonModePtr {
+		fmt.Printf("%s", jsh.Fallback("df"))
+	} else {
+		runJsonMode()
+	}
+}
diff --git a/df/main_test.go b/df/main_test.go
new file mode 100644
index 0000000..003cd8c
--- /dev/null
+++ b/df/main_test.go
@@ -0,0 +1,22 @@
+package main
+
+import (
+	"jsh"
+	"reflect"
+	"testing"
+)
+
+func TestPsOutputToProcesses(t *testing.T) {
+	psOutput := `USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
+root         1  0.0  0.1  26204  4916 ?        Ss   00:39   0:00 /sbin/init
+root         2  0.0  0.0      0     0 ?        S    00:39   0:00 [kthreadd]`
+	processes := PsOutputToProcesses(psOutput)
+	expected := []jsh.Process{jsh.Process{"root", "1", "0.0", "0.1", "26204",
+		"4916", "?", "Ss", "00:39", "0:00", "/sbin/init"},
+		jsh.Process{"root", "2", "0.0", "0.0", "0", "0", "?", "S", "00:39",
+			"0:00", "[kthreadd]"}}
+	actual := *processes
+	if !reflect.DeepEqual(expected, actual) {
+		t.Errorf("Processes not parsed correctly.\n%s != %s", expected, actual)
+	}
+}
diff --git a/filesystem.go b/filesystem.go
new file mode 100644
index 0000000..728827a
--- /dev/null
+++ b/filesystem.go
@@ -0,0 +1,35 @@
+/* File for Filesystem-related structs and methods */
+
+package jsh
+
+import (
+	"errors"
+	"strconv"
+)
+
+// Filesystem is a struct for marshalling into JSON output for the df utility.
+type Filesystem struct {
+	Name       string
+	Size       int
+	Used       int
+	Available  int
+	MountPoint string
+}
+
+// NewFilesystem
+func NewFilesystem(args []string) (procPtr *Filesystem, err error) {
+	err = nil
+	// 11 = number of fields in the Filesystem struct
+	if len(args) != 5 {
+		procPtr = &Filesystem{}
+		err = errors.New("Unexpected number of columns")
+	} else {
+		// TODO: add error checking
+		size, _ := strconv.Atoi(args[1])
+		used, _ := strconv.Atoi(args[2])
+		available, _ := strconv.Atoi(args[2])
+		procPtr = &Filesystem{
+			args[0], size, used, available, args[4]}
+	}
+	return
+}
diff --git a/filesystem_test.go b/filesystem_test.go
new file mode 100644
index 0000000..dfa7ecb
--- /dev/null
+++ b/filesystem_test.go
@@ -0,0 +1,28 @@
+package jsh
+
+import "testing"
+
+func TestNewFilesystem(t *testing.T) {
+	tooManyArgs := []string{"1", "2", "3", "4"}
+	_, err := NewFilesystem(tooManyArgs)
+	if err == nil {
+		t.Errorf("Passing 4 strings should raise an error")
+	}
+
+	tooFewArgs := []string{"1", "2", "3", "4", "5", "6"}
+	_, err = NewFilesystem(tooFewArgs)
+	if err == nil {
+		t.Errorf("Passing 6 strings should raise an error")
+	}
+
+	justRightArgs := []string{"1", "2", "3", "4", "5"}
+	proc, err := NewFilesystem(justRightArgs)
+	if err != nil {
+		t.Errorf("Passing 5 strings should not raise an error")
+	}
+	expected := Filesystem{"1", "2", "3", "4", "5"}
+	actual := *proc
+	if expected != actual {
+		t.Errorf("Filesystem was incorrectly generated:\n%s != %s", expected, actual)
+	}
+}