Add Display Free Disk Space as a unix til

README.md

@@ -7,7 +7,7 @@ variety of languages and technologies. These are things that don't really
 warrant a full blog post. These are mostly things I learn by pairing with
 smart people at [Hashrocket](http://hashrocket.com/).
 
-_417 TILs and counting..._
+_418 TILs and counting..._
 
 ---
 
@@ -365,6 +365,7 @@ _417 TILs and counting..._
 - [Copying File Contents To System Paste Buffer](unix/copying-file-contents-to-system-paste-buffer.md)
 - [Create A File Descriptor with Process Substitution](unix/create-a-file-descriptor-with-process-substitution.md)
 - [Curling With Basic Auth Credentials](unix/curling-with-basic-auth-credentials.md)
+- [Display Free Disk Space](unix/display-free-disk-space.md)
 - [Do Not Overwrite Existing Files](unix/do-not-overwrite-existing-files.md)
 - [Exclude A Directory With Find](unix/exclude-a-directory-with-find.md)
 - [File Type Info With File](unix/file-type-info-with-file.md)

unix/display-free-disk-space.md

@@ -0,0 +1,23 @@
+# Display Free Disk Space
+
+The `df` utility is a handy way to display the free disk space available on
+on a specific file system or all mounted file systems.
+
+Use `df` with the `-h` flag to display the disk space usage and availability
+in a human-readable format.
+
+Here is the output from a linode box of mine:
+
+```bash
+df -h
+Filesystem      Size  Used Avail Use% Mounted on
+/dev/xvda        20G  3.8G   16G  20% /
+none            4.0K     0  4.0K   0% /sys/fs/cgroup
+devtmpfs        994M  4.0K  994M   1% /dev
+none            200M  196K  199M   1% /run
+none            5.0M     0  5.0M   0% /run/lock
+none            996M     0  996M   0% /run/shm
+none            100M     0  100M   0% /run/user
+```
+
+h/t Josh Davey