Add the NSH df command

git-svn-id: https://nuttx.svn.sourceforge.net/svnroot/nuttx/trunk@5007 7fd9a85b-ad96-42d3-883c-3090e2eb8679

6 files changed, 196 insertions, 96 deletions

diff --git a/apps/ChangeLog.txt b/apps/ChangeLog.txt
index ecba285890..8cd30ae830 100755
--- a/apps/ChangeLog.txt
+++ b/apps/ChangeLog.txt
@@ -268,3 +268,5 @@
 	* apps/nshlib/nsh_mntcmds.c:  Separated mount-related commands out of
 	  nsh_fscmds.c.  Extended to the mount command so that if no arguments
 	  are provided, then the current mountpoints are enumerated.
+	* apps/nshlib/nsh_mntcmds.c:  Add an NSH df command to list the
+	  properties of mounted file systems.
diff --git a/apps/nshlib/README.txt b/apps/nshlib/README.txt
index 45d14f30d7..543b9a448d 100644
--- a/apps/nshlib/README.txt
+++ b/apps/nshlib/README.txt
@@ -308,6 +308,22 @@ o dd if=<infile> of=<outfile> [bs=<sectsize>] [count=<sectors>] [skip=<sectors>]
      brw-rw-rw-       0 ram0
     nsh> dd if=/dev/ram0 of=/dev/null
 
+o df
+
+  Show the state of each mounted volume
+
+  Example:
+
+  nsh> mount
+   /etc type romfs
+    /tmp type vfat
+  nsh> df
+    Block  Number
+    Size   Blocks     Used Available Mounted on
+      64        6        6         0 /etc
+     512      985        2       983 /tmp
+  nsh> 
+
 o echo [<string|$name> [<string|$name>...]]
 
   Copy the sequence of strings and expanded environment variables to
@@ -808,6 +824,7 @@ Command Dependencies on Configuration Settings
   cd         !CONFIG_DISABLE_ENVIRON && CONFIG_NFILE_DESCRIPTORS > 0
   cp         CONFIG_NFILE_DESCRIPTORS > 0
   dd         CONFIG_NFILE_DESCRIPTORS > 0
+  df         !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_READABLE (see note 3)
   echo       --
   exec       --
   exit       --
@@ -858,18 +875,19 @@ settings.  All of these settings make the configuration of NSH potentially compl
 also allow it to squeeze into very small memory footprints.
 
   CONFIG_NSH_DISABLE_CAT,      CONFIG_NSH_DISABLE_CD,       CONFIG_NSH_DISABLE_CP,
-  CONFIG_NSH_DISABLE_DD,       CONFIG_NSH_DISABLE_ECHO,     CONFIG_NSH_DISABLE_EXEC,
-  CONFIG_NSH_DISABLE_EXIT,     CONFIG_NSH_DISABLE_FREE,     CONFIG_NSH_DISABLE_GET,
-  CONFIG_NSH_DISABLE_HELP,     CONFIG_NSH_DISABLE_IFCONFIG, CONFIG_NSH_DISABLE_KILL,
-  CONFIG_NSH_DISABLE_LOSETUP,  CONFIG_NSH_DISABLE_LS,       CONFIG_NSH_DISABLE_MB,
-  CONFIG_NSH_DISABLE_MKDIR,    CONFIG_NSH_DISABLE_MKFATFS,  CONFIG_NSH_DISABLE_MKFIFO,
-  CONFIG_NSH_DISABLE_MKRD,     CONFIG_NSH_DISABLE_MH,       CONFIG_NSH_DISABLE_MOUNT,
-  CONFIG_NSH_DISABLE_MW,       CONFIG_NSH_DISABLE_MV,       CONFIG_NSH_DISABLE_NFSMOUNT,
-  CONFIG_NSH_DISABLE_PS,       CONFIG_NSH_DISABLE_PING,     CONFIG_NSH_DISABLE_PUT,
-  CONFIG_NSH_DISABLE_PWD,      CONFIG_NSH_DISABLE_RM,       CONFIG_NSH_DISABLE_RMDIR,
-  CONFIG_NSH_DISABLE_SET,      CONFIG_NSH_DISABLE_SH,       CONFIG_NSH_DISABLE_SLEEP,
-  CONFIG_NSH_DISABLE_TEST,     CONFIG_NSH_DISABLE_UMOUNT,   CONFIG_NSH_DISABLE_UNSET,
-  CONFIG_NSH_DISABLE_USLEEP,   CONFIG_NSH_DISABLE_WGET,     CONFIG_NSH_DISABLE_XD
+  CONFIG_NSH_DISABLE_DD,       CONFIG_NSH_DISABLE_DF,       CONFIG_NSH_DISABLE_ECHO,
+  CONFIG_NSH_DISABLE_EXEC,     CONFIG_NSH_DISABLE_EXIT,     CONFIG_NSH_DISABLE_FREE,
+  CONFIG_NSH_DISABLE_GET,      CONFIG_NSH_DISABLE_HELP,     CONFIG_NSH_DISABLE_IFCONFIG,
+  CONFIG_NSH_DISABLE_KILL,     CONFIG_NSH_DISABLE_LOSETUP,  CONFIG_NSH_DISABLE_LS,
+  CONFIG_NSH_DISABLE_MB,       CONFIG_NSH_DISABLE_MKDIR,    CONFIG_NSH_DISABLE_MKFATFS,
+  CONFIG_NSH_DISABLE_MKFIFO,   CONFIG_NSH_DISABLE_MKRD,     CONFIG_NSH_DISABLE_MH,
+  CONFIG_NSH_DISABLE_MOUNT,    CONFIG_NSH_DISABLE_MW,       CONFIG_NSH_DISABLE_MV,
+  CONFIG_NSH_DISABLE_NFSMOUNT, CONFIG_NSH_DISABLE_PS,       CONFIG_NSH_DISABLE_PING,
+  CONFIG_NSH_DISABLE_PUT,      CONFIG_NSH_DISABLE_PWD,      CONFIG_NSH_DISABLE_RM,
+  CONFIG_NSH_DISABLE_RMDIR,    CONFIG_NSH_DISABLE_SET,      CONFIG_NSH_DISABLE_SH,
+  CONFIG_NSH_DISABLE_SLEEP,    CONFIG_NSH_DISABLE_TEST,     CONFIG_NSH_DISABLE_UMOUNT,
+  CONFIG_NSH_DISABLE_UNSET,    CONFIG_NSH_DISABLE_USLEEP,   CONFIG_NSH_DISABLE_WGET,
+  CONFIG_NSH_DISABLE_XD
 
 NSH-Specific Configuration Settings
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/apps/nshlib/nsh.h b/apps/nshlib/nsh.h
index e4fb1e43e1..439c2ffd10 100644
--- a/apps/nshlib/nsh.h
+++ b/apps/nshlib/nsh.h
@@ -508,6 +508,9 @@ void nsh_usbtrace(void);
        int cmd_mkfifo(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 #   endif
 #   ifdef CONFIG_FS_READABLE
+#     ifndef CONFIG_NSH_DISABLE_DF
+         int cmd_df(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
+#     endif
 #     ifndef CONFIG_NSH_DISABLE_MOUNT
          int cmd_mount(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 #     endif
diff --git a/apps/nshlib/nsh_mntcmds.c b/apps/nshlib/nsh_mntcmds.c
index 054119e022..b5935bdea1 100644
--- a/apps/nshlib/nsh_mntcmds.c
+++ b/apps/nshlib/nsh_mntcmds.c
@@ -77,11 +77,33 @@
  ****************************************************************************/
 
 /****************************************************************************
+ * Name: df_handler
+ ****************************************************************************/
+
+#if CONFIG_NFILE_DESCRIPTORS > 0 && !defined(CONFIG_DISABLE_MOUNTPOINT) && \
+    defined(CONFIG_FS_READABLE) && !defined(CONFIG_NSH_DISABLE_MOUNT)
+static int df_handler(FAR const char *mountpoint,
+                      FAR struct statfs *statbuf, FAR void *arg)
+{
+  FAR struct nsh_vtbl_s *vtbl = (FAR struct nsh_vtbl_s *)arg;
+
+  DEBUGASSERT(mountpoint && statbuf && vtbl);
+
+  nsh_output(vtbl, "%6ld %8ld %8ld  %8ld %s\n",
+             statbuf->f_bsize, statbuf->f_blocks,
+             statbuf->f_blocks - statbuf->f_bavail, statbuf->f_bavail,
+             mountpoint);
+
+  return OK;
+}
+#endif
+
+/****************************************************************************
  * Name: mount_handler
  ****************************************************************************/
 
-#if !defined(CONFIG_DISABLE_MOUNTPOINT) && CONFIG_NFILE_DESCRIPTORS > 0 && defined(CONFIG_FS_READABLE)
-#ifndef CONFIG_NSH_DISABLE_MOUNT
+#if CONFIG_NFILE_DESCRIPTORS > 0 && !defined(CONFIG_DISABLE_MOUNTPOINT) && \
+    defined(CONFIG_FS_READABLE) && !defined(CONFIG_NSH_DISABLE_MOUNT)
 static int mount_handler(FAR const char *mountpoint,
                          FAR struct statfs *statbuf, FAR void *arg)
 {
@@ -133,31 +155,44 @@ static int mount_handler(FAR const char *mountpoint,
   return OK;
 }
 #endif
-#endif
 
 /****************************************************************************
  * Name: mount_show
  ****************************************************************************/
 
-#if !defined(CONFIG_DISABLE_MOUNTPOINT) && CONFIG_NFILE_DESCRIPTORS > 0 && defined(CONFIG_FS_READABLE)
-#ifndef CONFIG_NSH_DISABLE_MOUNT
+#if CONFIG_NFILE_DESCRIPTORS > 0 && !defined(CONFIG_DISABLE_MOUNTPOINT) && \
+    defined(CONFIG_FS_READABLE) && !defined(CONFIG_NSH_DISABLE_MOUNT)
 static inline int mount_show(FAR struct nsh_vtbl_s *vtbl, FAR const char *progname)
 {
   return foreach_mountpoint(mount_handler, (FAR void *)vtbl);
 }
 #endif
-#endif
 
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
 
 /****************************************************************************
+ * Name: cmd_df
+ ****************************************************************************/
+
+#if CONFIG_NFILE_DESCRIPTORS > 0 && !defined(CONFIG_DISABLE_MOUNTPOINT) && \
+    defined(CONFIG_FS_READABLE) && !defined(CONFIG_NSH_DISABLE_DF)
+int cmd_df(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
+{
+  nsh_output(vtbl, "  Block  Number\n");
+  nsh_output(vtbl, "  Size   Blocks     Used Available Mounted on\n");
+
+  return foreach_mountpoint(df_handler, (FAR void *)vtbl);
+}
+#endif
+
+/****************************************************************************
  * Name: cmd_mount
  ****************************************************************************/
 
-#if !defined(CONFIG_DISABLE_MOUNTPOINT) && CONFIG_NFILE_DESCRIPTORS > 0 && defined(CONFIG_FS_READABLE)
-#ifndef CONFIG_NSH_DISABLE_MOUNT
+#if CONFIG_NFILE_DESCRIPTORS > 0 && !defined(CONFIG_DISABLE_MOUNTPOINT) && \
+    defined(CONFIG_FS_READABLE) && !defined(CONFIG_NSH_DISABLE_MOUNT)
 int cmd_mount(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
 {
   char *source;
@@ -247,15 +282,13 @@ int cmd_mount(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
   return ret;
 }
 #endif
-#endif
 
 /****************************************************************************
  * Name: cmd_nfsmount
  ****************************************************************************/
 
-#if !defined(CONFIG_DISABLE_MOUNTPOINT) && CONFIG_NFILE_DESCRIPTORS > 0 && \
-    defined(CONFIG_NET) && defined(CONFIG_NFS)
-#ifndef CONFIG_NSH_DISABLE_NFSMOUNT
+#if CONFIG_NFILE_DESCRIPTORS > 0 && !defined(CONFIG_DISABLE_MOUNTPOINT) && \
+    defined(CONFIG_NET) && defined(CONFIG_NFS) && !defined(CONFIG_NSH_DISABLE_NFSMOUNT)
 int cmd_nfsmount(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
 {
   struct nfs_args data;
@@ -354,14 +387,13 @@ int cmd_nfsmount(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
   return ret;
 }
 #endif
-#endif
 
 /****************************************************************************
  * Name: cmd_umount
  ****************************************************************************/
 
-#if !defined(CONFIG_DISABLE_MOUNTPOINT) && CONFIG_NFILE_DESCRIPTORS > 0 && defined(CONFIG_FS_READABLE)
-#ifndef CONFIG_NSH_DISABLE_UMOUNT
+#if CONFIG_NFILE_DESCRIPTORS > 0 && !defined(CONFIG_DISABLE_MOUNTPOINT) && \
+    defined(CONFIG_FS_READABLE) && !defined(CONFIG_NSH_DISABLE_UMOUNT)
 int cmd_umount(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
 {
   char *fullpath = nsh_getfullpath(vtbl, argv[1]);
@@ -378,7 +410,7 @@ int cmd_umount(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
         }
       nsh_freefullpath(fullpath);
     }
+
   return ret;
 }
 #endif
-#endif
diff --git a/apps/nshlib/nsh_parse.c b/apps/nshlib/nsh_parse.c
index d62f6b5a90..00319a98b9 100644
--- a/apps/nshlib/nsh_parse.c
+++ b/apps/nshlib/nsh_parse.c
@@ -163,13 +163,18 @@ static const struct cmdmap_s g_cmdmap[] =
   { "date",     cmd_date,     1, 3, "[-s \"MMM DD HH:MM:SS YYYY\"]" },
 #endif
 
-#if CONFIG_NFILE_DESCRIPTORS > 0
-# ifndef CONFIG_NSH_DISABLE_DD
+#if CONFIG_NFILE_DESCRIPTORS > 0 && !defined(CONFIG_NSH_DISABLE_DD)
   { "dd",       cmd_dd,       3, 6, "if=<infile> of=<outfile> [bs=<sectsize>] [count=<sectors>] [skip=<sectors>]" },
 # endif
-# if defined(CONFIG_SYSLOG) && defined(CONFIG_RAMLOG_SYSLOG) && !defined(CONFIG_NSH_DISABLE_DMESG)
+
+#if CONFIG_NFILE_DESCRIPTORS > 0 && !defined(CONFIG_DISABLE_MOUNTPOINT) && \
+    defined(CONFIG_FS_READABLE) && !defined(CONFIG_NSH_DISABLE_DF)
+  { "df",       cmd_df,       1, 1, NULL },
+#endif
+
+#if CONFIG_NFILE_DESCRIPTORS > 0 && defined(CONFIG_SYSLOG) && \
+    defined(CONFIG_RAMLOG_SYSLOG) && !defined(CONFIG_NSH_DISABLE_DMESG)
   { "dmesg",    cmd_dmesg,    1, 1, NULL },
-# endif
 #endif
 
 #ifndef CONFIG_NSH_DISABLE_ECHO
diff --git a/nuttx/Documentation/NuttShell.html b/nuttx/Documentation/NuttShell.html
index 86014074f4..e561a9bb3a 100644
--- a/nuttx/Documentation/NuttShell.html
+++ b/nuttx/Documentation/NuttShell.html
@@ -119,193 +119,199 @@
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdecho">2.7 Echo Strings and Variables (echo)</a>
+    <a href="#cmddf">2.7 Show volume status (df)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdexec">2.8 Execute User Code (exec)</a>
+    <a href="#cmdecho">2.8 Echo Strings and Variables (echo)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdexit">2.9 Exit NSH (exit)</a>
+    <a href="#cmdexec">2.9 Execute User Code (exec)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdfree">2.10 Show Memory Manager Status (free)</a>
+    <a href="#cmdexit">2.10 Exit NSH (exit)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdget">2.11 Get File Via TFTP (get)</a>
+    <a href="#cmdfree">2.11 Show Memory Manager Status (free)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdhelp">2.12 Show Usage Command Usage (help)</a>
+    <a href="#cmdget">2.12 Get File Via TFTP (get)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdifconfig">2.13 Show Network Configuration (ifconfig)</a>
+    <a href="#cmdhelp">2.13 Show Usage Command Usage (help)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdkill">2.14 Send a signal to a task (kill)</a>
+    <a href="#cmdifconfig">2.14 Show Network Configuration (ifconfig)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdlosetup">2.15 Setup/teardown the Loop Device (losetup)</a>
+    <a href="#cmdkill">2.15 Send a signal to a task (kill)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdls">2.16 List Directory Contents (ls)</a>
+    <a href="#cmdlosetup">2.16 Setup/teardown the Loop Device (losetup)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdmbhw">2.17 Access Memory (mb, mh, and mw)</a>
+    <a href="#cmdls">2.17 List Directory Contents (ls)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdps">2.18 Show Current Tasks and Threads (ps)</a>
+    <a href="#cmdmbhw">2.18 Access Memory (mb, mh, and mw)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdmkdir">2.19 Create a Directory (mkdir)</a>
+    <a href="#cmdps">2.19 Show Current Tasks and Threads (ps)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdmkfatfs">2.20 Create a FAT Filesystem (mkfatfs)</a>
+    <a href="#cmdmkdir">2.20 Create a Directory (mkdir)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdmkfifo">2.21 Create a FIFO (mkfifo)</a>
+    <a href="#cmdmkfatfs">2.21 Create a FAT Filesystem (mkfatfs)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdmkrd">2.22 Create a RAMDISK (mkrd)</a>
+    <a href="#cmdmkfifo">2.22 Create a FIFO (mkfifo)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdmount">2.23 Mount a File System (mount)</a>
+    <a href="#cmdmkrd">2.23 Create a RAMDISK (mkrd)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdmv">2.24 Rename a File (mv)</a>
+    <a href="#cmdmount">2.24 Mount a File System (mount)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdnfsmount">2.25 Mount an NFS file system (nfsmount)</a>
+    <a href="#cmdmv">2.25 Rename a File (mv)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdping">2.26 Check Network Peer (ping)</a>
+    <a href="#cmdnfsmount">2.26 Mount an NFS file system (nfsmount)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdput">2.27 Send File Via TFTP (put)</a>
+    <a href="#cmdping">2.27 Check Network Peer (ping)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdpwd">2.28 Show Current Working Directory (pwd)</a>
+    <a href="#cmdput">2.28 Send File Via TFTP (put)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdrm">2.29 Remove a File (rm)</a>
+    <a href="#cmdpwd">2.29 Show Current Working Directory (pwd)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdrmdir">2.30 Remove a Directory (rmdir)</a>
+    <a href="#cmdrm">2.30 Remove a File (rm)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdset">2.31 Set an Environment Variable (set)</a>
+    <a href="#cmdrmdir">2.31 Remove a Directory (rmdir)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdsh">2.32 Execute an NSH Script (sh)</a>
+    <a href="#cmdset">2.32 Set an Environment Variable (set)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdsleep">2.33 Wait for Seconds (sleep)</a>
+    <a href="#cmdsh">2.33 Execute an NSH Script (sh)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdunmount">2.34 Unmount a File System (umount)</a>
+    <a href="#cmdsleep">2.34 Wait for Seconds (sleep)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdunset">2.35 Unset an Environment Variable (unset)</a>
+    <a href="#cmdunmount">2.35 Unmount a File System (umount)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdusleep">2.36 Wait for Microseconds (usleep)</a>
+    <a href="#cmdunset">2.36 Unset an Environment Variable (unset)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdwget">2.37 Get File Via HTTP (wget)</a>
+    <a href="#cmdusleep">2.37 Wait for Microseconds (usleep)</a>
   </td>
 </tr>
 <tr>
   <td><br></td>
   <td>
-    <a href="#cmdxd">2.38 Hexadecimal Dump (xd)</a>
+    <a href="#cmdwget">2.38 Get File Via HTTP (wget)</a>
+  </td>
+</tr>
+<tr>
+  <td><br></td>
+  <td>
+    <a href="#cmdxd">2.39 Hexadecimal Dump (xd)</a>
   </td>
 </tr>
 <tr>
@@ -872,7 +878,35 @@ nsh&gt; dd if=/dev/ram0 of=/dev/null
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdecho"><h2>2.7 Echo Strings and Variables (echo)</h2></a>
+    <a name="cmddf"><h2>2.7 Show Volument Status (df)</h2></a>
+  </td>
+  </tr>
+</table>
+<p><b>Command Syntax:</b></p>
+<ul><pre>
+df
+</pre></ul>
+<p>
+  <b>Synopsis</b>.
+    Show the state of each mounted volume.
+    As an example:
+</p>
+<ul><pre>
+nsh> mount
+ /etc type romfs
+  /tmp type vfat
+nsh> df
+  Block  Number
+  Size   Blocks     Used Available Mounted on
+    64        6        6         0 /etc
+   512      985        2       983 /tmp
+nsh> 
+</pre></ul>
+
+<table width ="100%">
+  <tr bgcolor="#e4e4e4">
+  <td>
+    <a name="cmdecho"><h2>2.8 Echo Strings and Variables (echo)</h2></a>
   </td>
   </tr>
 </table>
@@ -890,7 +924,7 @@ echo [&lt;string|$name&gt; [&lt;string|$name&gt;...]]
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdexec"><h2>2.8 Execute User Code (exec)</h2></a>
+    <a name="cmdexec"><h2>2.9 Execute User Code (exec)</h2></a>
   </td>
   </tr>
 </table>
@@ -909,7 +943,7 @@ exec &lt;hex-address&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdexit"><h2>2.9 Exit NSH (exit)</h2></a>
+    <a name="cmdexit"><h2>2.10 Exit NSH (exit)</h2></a>
   </td>
   </tr>
 </table>
@@ -928,7 +962,7 @@ exit
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdfree"><h2>2.10 Show Memory Manager Status (free)</h2></a>
+    <a name="cmdfree"><h2>2.11 Show Memory Manager Status (free)</h2></a>
   </td>
   </tr>
 </table>
@@ -970,7 +1004,7 @@ nsh&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdget"><h2>2.11 Get File Via TFTP (get)</h2></a>
+    <a name="cmdget"><h2>2.12 Get File Via TFTP (get)</h2></a>
   </td>
   </tr>
 </table>
@@ -1005,7 +1039,7 @@ get [-b|-n] [-f &lt;local-path&gt;] -h &lt;ip-address&gt; &lt;remote-path&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdhelp"><h2>2.12 Show Usage Command Usage (help)</h2></a>
+    <a name="cmdhelp"><h2>2.13 Show Usage Command Usage (help)</h2></a>
   </td>
   </tr>
 </table>
@@ -1022,7 +1056,7 @@ help
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdifconfig"><h2>2.13 Show Network Configuration (ifconfig)</h2></a>
+    <a name="cmdifconfig"><h2>2.14 Show Network Configuration (ifconfig)</h2></a>
   </td>
   </tr>
 </table>
@@ -1073,7 +1107,7 @@ ifconfig nic_name ip_address
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdkill"><h2>2.14 Send a signal to a task (kill)</h2></a>
+    <a name="cmdkill"><h2>2.15 Send a signal to a task (kill)</h2></a>
   </td>
   </tr>
 </table>
@@ -1114,7 +1148,7 @@ nsh&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdlosetup"><h2>2.15 Setup/teardown the Loop Device (losetup)</h2></a>
+    <a name="cmdlosetup"><h2>2.16 Setup/teardown the Loop Device (losetup)</h2></a>
   </td>
   </tr>
 </table>
@@ -1167,7 +1201,7 @@ losetup d &lt;dev-path&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdls"><h2>2.16 List Directory Contents (ls)</h2></a>
+    <a name="cmdls"><h2>2.17 List Directory Contents (ls)</h2></a>
   </td>
   </tr>
 </table>
@@ -1204,7 +1238,7 @@ ls [-lRs] &lt;dir-path&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdmbhw"><h2>2.17 Access Memory (mb, mh, and mw)</h2></a>
+    <a name="cmdmbhw"><h2>2.18 Access Memory (mb, mh, and mw)</h2></a>
   </td>
   </tr>
 </table>
@@ -1258,7 +1292,7 @@ nsh&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdps"><h2>2.18 Show Current Tasks and Threads (ps)</h2></a>
+    <a name="cmdps"><h2>2.19 Show Current Tasks and Threads (ps)</h2></a>
   </td>
   </tr>
 </table>
@@ -1284,7 +1318,7 @@ nsh&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdmkdir"><h2>2.19 Create a Directory (mkdir)</h2></a>
+    <a name="cmdmkdir"><h2>2.20 Create a Directory (mkdir)</h2></a>
   </td>
 </tr>
 </table>
@@ -1319,7 +1353,7 @@ nsh>
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdmkfatfs"><h2>2.20 Create a FAT Filesystem (mkfatfs)</h2></a>
+    <a name="cmdmkfatfs"><h2>2.21 Create a FAT Filesystem (mkfatfs)</h2></a>
   </td>
 </tr>
 </table>
@@ -1339,7 +1373,7 @@ mkfatfs &lt;path&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdmkfifo"><h2>2.21 Create a FIFO (mkfifo)</h2></a>
+    <a name="cmdmkfifo"><h2>2.22 Create a FIFO (mkfifo)</h2></a>
   </td>
 </tr>
 </table>
@@ -1377,7 +1411,7 @@ nsh>
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdmkrd"><h2>2.22 Create a RAMDISK (mkrd)</h2></a>
+    <a name="cmdmkrd"><h2>2.23 Create a RAMDISK (mkrd)</h2></a>
   </td>
 </tr>
 </table>
@@ -1428,7 +1462,7 @@ nsh&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdmount"><h2>2.23 Mount a File System (mount)</h2></a>
+    <a name="cmdmount"><h2>2.24 Mount a File System (mount)</h2></a>
   </td>
 </tr>
 </table>
@@ -1507,7 +1541,7 @@ nsh> mount
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdmv"><h2>2.24 Rename a File (mv)</h2></a>
+    <a name="cmdmv"><h2>2.25 Rename a File (mv)</h2></a>
   </td>
   </tr>
 </table>
@@ -1525,7 +1559,7 @@ mv &lt;old-path&gt; &lt;new-path&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdnfsmount"><h2>2.25 Mount an NFS file system (nfsmount)</h2></a>
+    <a name="cmdnfsmount"><h2>2.26 Mount an NFS file system (nfsmount)</h2></a>
   </td>
   </tr>
 </table>
@@ -1544,7 +1578,7 @@ nfsmount &lt;server-address&gt; &lt;mount-point&gt; &lt;remote-path&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdping"><h2>2.26 Check Network Peer (ping)</h2></a>
+    <a name="cmdping"><h2>2.27 Check Network Peer (ping)</h2></a>
   </td>
   </tr>
 </table>
@@ -1577,7 +1611,7 @@ nsh&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdput"><h2>2.27 Send File Via TFTP (put)</h2></a>
+    <a name="cmdput"><h2>2.28 Send File Via TFTP (put)</h2></a>
   </td>
   </tr>
 </table>
@@ -1612,7 +1646,7 @@ put [-b|-n] [-f &lt;remote-path&gt;] -h &lt;ip-address&gt; &lt;local-path&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdpwd"><h2>2.28 Show Current Working Directory (pwd)</h2></a>
+    <a name="cmdpwd"><h2>2.29 Show Current Working Directory (pwd)</h2></a>
   </td>
   </tr>
 </table>
@@ -1642,7 +1676,7 @@ nsh&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdrm"><h2>2.29 Remove a File (rm)</h2></a>
+    <a name="cmdrm"><h2>2.30 Remove a File (rm)</h2></a>
   </td>
 </tr>
 </table>
@@ -1676,7 +1710,7 @@ nsh>
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdrmdir"><h2>2.30 Remove a Directory (rmdir)</h2></a>
+    <a name="cmdrmdir"><h2>2.31 Remove a Directory (rmdir)</h2></a>
   </td>
 </tr>
 </table>
@@ -1711,7 +1745,7 @@ nsh>
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdset"><h2>2.31 Set an Environment Variable (set)</h2></a>
+    <a name="cmdset"><h2>2.32 Set an Environment Variable (set)</h2></a>
   </td>
   </tr>
 </table>
@@ -1737,7 +1771,7 @@ nsh&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdsh"><h2>2.32 Execute an NSH Script (sh)</h2></a>
+    <a name="cmdsh"><h2>2.33 Execute an NSH Script (sh)</h2></a>
   </td>
   </tr>
 </table>
@@ -1755,7 +1789,7 @@ sh &lt;script-path&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdsleep"><h2>2.33 Wait for Seconds (sleep)</h2></a>
+    <a name="cmdsleep"><h2>2.34 Wait for Seconds (sleep)</h2></a>
   </td>
   </tr>
 </table>
@@ -1772,7 +1806,7 @@ sleep &lt;sec&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdunmount"><h2>2.34 Unmount a File System (umount)</h2></a>
+    <a name="cmdunmount"><h2>2.35 Unmount a File System (umount)</h2></a>
   </td>
 </tr>
 </table>
@@ -1802,7 +1836,7 @@ nsh>
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdunset"><h2>2.35 Unset an Environment Variable (unset)</h2></a>
+    <a name="cmdunset"><h2>2.36 Unset an Environment Variable (unset)</h2></a>
   </td>
   </tr>
 </table>
@@ -1828,7 +1862,7 @@ nsh&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdusleep"><h2>2.36 Wait for Microseconds (usleep)</h2></a>
+    <a name="cmdusleep"><h2>2.37 Wait for Microseconds (usleep)</h2></a>
   </td>
   </tr>
 </table>
@@ -1872,7 +1906,7 @@ wget [-o &lt;local-path&gt;] &lt;url&gt;
 <table width ="100%">
   <tr bgcolor="#e4e4e4">
   <td>
-    <a name="cmdxd"><h2>2.37 Hexadecimal dump (xd)</h2></a>
+    <a name="cmdxd"><h2>2.38 Hexadecimal dump (xd)</h2></a>
   </td>
   </tr>
 </table>
@@ -1966,6 +2000,11 @@ nsh>
     <td><code>CONFIG_NSH_DISABLE_DD</code></td>
   </tr>
   <tr>
+    <td><b><code>df</code></b></td>
+    <td>!<code>CONFIG_DISABLE_MOUNTPOINT</code> &amp;&amp; <code>CONFIG_NFILE_DESCRIPTORS</code> &gt; 0 &amp;&amp; <code>CONFIG_FS_READABLE</code><sup>3</sup></td>
+    <td><code>CONFIG_NSH_DISABLE_DF</code></td>
+  </tr>
+  <tr>
     <td><b><code>echo</code></b></td>
     <td><br></td>
     <td><code>CONFIG_NSH_DISABLE_ECHO</code></td>
@@ -2647,9 +2686,10 @@ nsh>
   <li><a href="#currentwd">Current working directory</a></li>
   <li><a href="#cmddate"><code>date</code></a></li>
   <li><a href="#cmddd"><code>dd</code></a></li>
-  <li><a href="#cmdecho"><code>echo</code></a></li>
+  <li><a href="#cmddf"><code>df</code></a></li>
 </ul></td>
 <td></ul>
+  <li><a href="#cmdecho"><code>echo</code></a></li>
   <li><a href="#environvars">Environment Variables</a></li>
   <li><a href="#startupscript"><code>/etc/init.d/rcS</code></a>
   <li><a href="#cmdexec"><code>exec</code></a></li>