Add test and [ commands

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@864 42af7a65-404d-4744-a932-0658087f49c3

8 files changed, 524 insertions, 13 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index 75dd9c163..a27c01c5a 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -440,4 +440,5 @@
 	* fseek() needs to discard bytes buffered by ungetc().
 	* Corrected ftell() return value.
 	* Added fsetpos() and fgetpos().
+	* NSH now supports 'test' and '[' commands
 
diff --git a/nuttx/Documentation/NuttX.html b/nuttx/Documentation/NuttX.html
index 0b33ac548..c96db7b60 100644
--- a/nuttx/Documentation/NuttX.html
+++ b/nuttx/Documentation/NuttX.html
@@ -456,7 +456,7 @@
 </table>
 
 <p>
-  The 2tth release of NuttX (nuttx-0.3.13) is available for download
+  The 25th release of NuttX (nuttx-0.3.13) is available for download
   from the <a href="http://sourceforge.net/project/showfiles.php?group_id=189573">SourceForge</a>
   website.
   The change log associated with the release is available <a href="#currentrelease">here</a>.
@@ -1067,6 +1067,7 @@ nuttx-0.3.14 2008-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 	* fseek() needs to discard bytes buffered by ungetc().
 	* Corrected ftell() return value.
 	* Added fsetpos() and fgetpos().
+	* NSH now supports 'test' and '[' commands
 
 pascal-0.1.3 2008-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 
diff --git a/nuttx/examples/README.txt b/nuttx/examples/README.txt
index 82055e397..4847d3d25 100644
--- a/nuttx/examples/README.txt
+++ b/nuttx/examples/README.txt
@@ -37,6 +37,7 @@ examples/nsh
 
   Command    Depends on Configuration
   ---------- --------------------------
+  [          !CONFIG_EXAMPLES_NSH_DISABLESCRIPT
   cat        CONFIG_NFILE_DESCRIPTORS > 0
   cd         !CONFIG_DISABLE_ENVIRON && CONFIG_NFILE_DESCRIPTORS > 0
   cp         CONFIG_NFILE_DESCRIPTORS > 0
@@ -54,15 +55,38 @@ examples/nsh
   mount      !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_FAT
   ps         --
   pwd        !CONFIG_DISABLE_ENVIRON && CONFIG_NFILE_DESCRIPTORS > 0
-  set        !CONFIG_DISABLE_ENVIRON
-  sleep      !CONFIG_DISABLE_SIGNALS
-  sh         CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_NFILE_STREAMS > 0
   rm         !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0
   rmdir      !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0
+  set        !CONFIG_DISABLE_ENVIRON
+  sh         CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_NFILE_STREAMS > 0 && !CONFIG_EXAMPLES_NSH_DISABLESCRIPT
+  sleep      !CONFIG_DISABLE_SIGNALS
+  test       !CONFIG_EXAMPLES_NSH_DISABLESCRIPT
   umount     !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_FAT
   unset      !CONFIG_DISABLE_ENVIRON
   usleep     !CONFIG_DISABLE_SIGNALS
 
+  Test syntax:
+
+    expression = simple-expression | !expression |
+                 expression -o expression | expression -a expression
+
+    simple-expression = unary-expression | binary-expression
+
+    unary-expression = string-unary | file-unary
+
+    string-unary = -n string | -z string
+
+    file-unary = -b file | -c file | -d file | -e file | -f file |
+                 -r file | -s file | -w file
+
+    binary-expression = string-binary | numeric-binary
+
+    string-binary = string = string | string == string | string != string
+
+    numeric-binary = integer -eq integer | integer -ge integer |
+                     integer -gt integer | integer -le integer |
+                     integer -lt integer | integer -ne integer
+
   Other behavior of NSH can be modified with the following settings in
   the configs/<board-name>/defconfig file:
 
@@ -87,6 +111,12 @@ examples/nsh
       The maximum number of nested if-then[-else]-fi sequences that
       are permissable.  Default: 3
 
+  * CONFIG_EXAMPLES_NSH_DISABLESCRIPT
+      This can be set to 'y' to suppress support for scripting.  This
+      setting disables the 'sh', 'test', and '[' commands and the
+      if-then[-else]-fi construct.  This would only be set on systems
+      where a minimal footprint is a necessity and scripting is not.
+
   * CONFIG_EXAMPLES_NSH_CONSOLE
       If CONFIG_EXAMPLES_NSH_CONSOLE is set to 'y', then a serial
       console front-end is selected.
diff --git a/nuttx/examples/nsh/Makefile b/nuttx/examples/nsh/Makefile
index db2f26677..5ff7e3c6a 100644
--- a/nuttx/examples/nsh/Makefile
+++ b/nuttx/examples/nsh/Makefile
@@ -53,6 +53,10 @@ ifeq ($(CONFIG_EXAMPLES_NSH_TELNET),y)
 CSRCS	+= nsh_telnetd.c
 endif
 
+ifneq ($(CONFIG_EXAMPLES_NSH_DISABLESCRIPT),y)
+CSRCS	+= nsh_test.c
+endif
+
 AOBJS	= $(ASRCS:.S=$(OBJEXT))
 COBJS	= $(CSRCS:.c=$(OBJEXT))
 
diff --git a/nuttx/examples/nsh/nsh.h b/nuttx/examples/nsh/nsh.h
index 76e2701ba..7afade195 100644
--- a/nuttx/examples/nsh/nsh.h
+++ b/nuttx/examples/nsh/nsh.h
@@ -163,7 +163,9 @@ struct nsh_parser_s
 #endif
   boolean   np_redirect; /* TRUE: Output from the last command was re-directed */
   boolean   np_fail;     /* TRUE: The last command failed */
+#ifndef CONFIG_EXAMPLES_NSH_DISABLESCRIPT
   ubyte     np_ndx;      /* Current index into np_st[] */
+#endif
 #ifndef CONFIG_DISABLE_PTHREAD
   int       np_nice;     /* "nice" value applied to last background cmd */
 #endif
@@ -172,7 +174,9 @@ struct nsh_parser_s
    * execution of commands that span multiple lines (like if-then-else-fi)
    */
 
+#ifndef CONFIG_EXAMPLES_NSH_DISABLESCRIPT
   struct nsh_state_s np_st[CONFIG_EXAMPLES_NSH_NESTDEPTH];
+#endif
 };
 
 struct nsh_vtbl_s
@@ -207,11 +211,11 @@ typedef int (*cmd_t)(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 
 extern const char g_nshgreeting[];
 extern const char g_nshprompt[];
+extern const char g_nshsyntax[];
 extern const char g_fmtargrequired[];
 extern const char g_fmtarginvalid[];
 extern const char g_fmtargrange[];
 extern const char g_fmtcmdnotfound[];
-extern const char g_fmtcmdnotimpl[];
 extern const char g_fmtnosuch[];
 extern const char g_fmttoomanyargs[];
 extern const char g_fmtdeepnesting[];
@@ -256,13 +260,18 @@ extern int cmd_mw(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 extern int cmd_mem(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 extern int cmd_ps(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 
+#ifndef CONFIG_EXAMPLES_NSH_DISABLESCRIPT
+extern int cmd_test(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
+extern int cmd_lbracket(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
+#endif
+
 #if CONFIG_NFILE_DESCRIPTORS > 0
   extern int cmd_cat(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
   extern int cmd_cp(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
   extern int cmd_ls(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
-# if CONFIG_NFILE_STREAMS > 0
+# if CONFIG_NFILE_STREAMS > 0 && !defined(CONFIG_EXAMPLES_NSH_DISABLESCRIPT)
   extern int cmd_sh(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
-# endif  /* CONFIG_NFILE_STREAMS */
+# endif  /* CONFIG_NFILE_STREAMS && !CONFIG_EXAMPLES_NSH_DISABLESCRIPT */
 # ifndef CONFIG_DISABLE_MOUNTPOINT
     extern int cmd_mkdir(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
     extern int cmd_mkfifo(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
diff --git a/nuttx/examples/nsh/nsh_fscmds.c b/nuttx/examples/nsh/nsh_fscmds.c
index b4f5161c1..458f1130e 100644
--- a/nuttx/examples/nsh/nsh_fscmds.c
+++ b/nuttx/examples/nsh/nsh_fscmds.c
@@ -905,7 +905,7 @@ int cmd_rmdir(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
  * Name: cmd_sh
  ****************************************************************************/
 
-#if CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_NFILE_STREAMS > 0
+#if  CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_NFILE_STREAMS > 0 && !defined(CONFIG_EXAMPLES_NSH_DISABLESCRIPT)
 int cmd_sh(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
 {
   char *fullpath;
diff --git a/nuttx/examples/nsh/nsh_main.c b/nuttx/examples/nsh/nsh_main.c
index f8c9bdb24..01f5ed690 100644
--- a/nuttx/examples/nsh/nsh_main.c
+++ b/nuttx/examples/nsh/nsh_main.c
@@ -128,6 +128,9 @@ static const char g_failure[]    = "1";
 
 static const struct cmdmap_s g_cmdmap[] =
 {
+#ifndef CONFIG_EXAMPLES_NSH_DISABLESCRIPT
+  { "[",        cmd_lbracket, 4, NSH_MAX_ARGUMENTS, "<expression> ]" },
+#endif
 #if CONFIG_NFILE_DESCRIPTORS > 0
   { "cat",      cmd_cat,      2, NSH_MAX_ARGUMENTS, "<path> [<path> [<path> ...]]" },
 #ifndef CONFIG_DISABLE_ENVIRON
@@ -169,19 +172,22 @@ static const struct cmdmap_s g_cmdmap[] =
 #if CONFIG_NFILE_DESCRIPTORS > 0 && !defined(CONFIG_DISABLE_ENVIRON)
   { "pwd",      cmd_pwd,      1, 1, NULL },
 #endif
-#ifndef CONFIG_DISABLE_ENVIRON
-  { "set",      cmd_set,      3, 3, "<name> <value>" },
-#endif
 #if !defined(CONFIG_DISABLE_MOUNTPOINT) && CONFIG_NFILE_DESCRIPTORS > 0
   { "rm",       cmd_rm,       2, 2, "<file-path>" },
   { "rmdir",    cmd_rmdir,    2, 2, "<dir-path>" },
 #endif
-#if  CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_NFILE_STREAMS > 0
+#ifndef CONFIG_DISABLE_ENVIRON
+  { "set",      cmd_set,      3, 3, "<name> <value>" },
+#endif
+#if  CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_NFILE_STREAMS > 0 && !defined(CONFIG_EXAMPLES_NSH_DISABLESCRIPT)
   { "sh",       cmd_sh,       2, 2, "<script-path>" },
 #endif  /* CONFIG_NFILE_DESCRIPTORS && CONFIG_NFILE_STREAMS */
 #ifndef CONFIG_DISABLE_SIGNALS
   { "sleep",    cmd_sleep,    2, 2, "<sec>" },
 #endif /* CONFIG_DISABLE_SIGNALS */
+#ifndef CONFIG_EXAMPLES_NSH_DISABLESCRIPT
+  { "test",     cmd_test,     3, NSH_MAX_ARGUMENTS, "<expression>" },
+#endif
 #if !defined(CONFIG_DISABLE_MOUNTPOINT) && CONFIG_NFILE_DESCRIPTORS > 0
 # ifdef CONFIG_FS_FAT /* Need at least one filesytem in configuration */
   { "umount",   cmd_umount,   2, 2, "<dir-path>" },
@@ -202,11 +208,11 @@ static const struct cmdmap_s g_cmdmap[] =
 
 const char g_nshgreeting[]       = "NuttShell (NSH)\n";
 const char g_nshprompt[]         = "nsh> ";
+const char g_nshsyntax[]         = "nsh: %s: syntax error\n";
 const char g_fmtargrequired[]    = "nsh: %s: missing required argument(s)\n";
 const char g_fmtarginvalid[]     = "nsh: %s: argument invalid\n";
 const char g_fmtargrange[]       = "nsh: %s: value out of range\n";
 const char g_fmtcmdnotfound[]    = "nsh: %s: command not found\n";
-const char g_fmtcmdnotimpl[]     = "nsh: %s: command not implemented\n";
 const char g_fmtnosuch[]         = "nsh: %s: no such %s: %s\n";
 const char g_fmttoomanyargs[]    = "nsh: %s: too many arguments\n";
 const char g_fmtdeepnesting[]    = "nsh: %s: nesting too deep\n";
@@ -237,6 +243,7 @@ static int cmd_help(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
 #else
   nsh_output(vtbl, "  <cmd> [> <file>|>> <file>]\n");
 #endif
+#ifndef CONFIG_EXAMPLES_NSH_DISABLESCRIPT
   nsh_output(vtbl, "OR\n");
   nsh_output(vtbl, "  if <cmd>\n");
   nsh_output(vtbl, "  then\n");
@@ -244,6 +251,7 @@ static int cmd_help(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
   nsh_output(vtbl, "  else\n");
   nsh_output(vtbl, "    [sequence of <cmd>]\n");
   nsh_output(vtbl, "  fi\n");
+#endif
   nsh_output(vtbl, "Where <cmd> is one of:\n");
   for (ptr = g_cmdmap; ptr->cmd; ptr++)
     {
@@ -569,6 +577,7 @@ char *nsh_argument(FAR struct nsh_vtbl_s *vtbl, char **saveptr)
  * Name: nsh_cmdenabled
  ****************************************************************************/
 
+#ifndef CONFIG_EXAMPLES_NSH_DISABLESCRIPT
 static inline boolean nsh_cmdenabled(FAR struct nsh_vtbl_s *vtbl)
 {
   struct nsh_parser_s *np = &vtbl->np;
@@ -593,11 +602,13 @@ static inline boolean nsh_cmdenabled(FAR struct nsh_vtbl_s *vtbl)
     }
   return ret;
 }
+#endif
 
 /****************************************************************************
  * Name: nsh_ifthenelse
  ****************************************************************************/
 
+#ifndef CONFIG_EXAMPLES_NSH_DISABLESCRIPT
 static inline int nsh_ifthenelse(FAR struct nsh_vtbl_s *vtbl, FAR char **ppcmd, FAR char **saveptr)
 {
   struct nsh_parser_s *np = &vtbl->np;
@@ -730,6 +741,7 @@ errout:
   np->np_st[0].ns_ifcond   = FALSE;
   return ERROR;
 }
+#endif
 
 /****************************************************************************
  * Name: nsh_saveresult
@@ -739,6 +751,7 @@ static inline int nsh_saveresult(FAR struct nsh_vtbl_s *vtbl, boolean result)
 {
   struct nsh_parser_s *np = &vtbl->np;
 
+#ifndef CONFIG_EXAMPLES_NSH_DISABLESCRIPT
   if (np->np_st[np->np_ndx].ns_state == NSH_PARSER_IF)
     {
       np->np_fail = FALSE;
@@ -746,6 +759,7 @@ static inline int nsh_saveresult(FAR struct nsh_vtbl_s *vtbl, boolean result)
       return OK;
     }
   else
+#endif
     {
       np->np_fail = result;
       return result ? ERROR : OK;
@@ -898,10 +912,12 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
 
   /* Handler if-then-else-fi */
 
+#ifndef CONFIG_EXAMPLES_NSH_DISABLESCRIPT
   if (nsh_ifthenelse(vtbl, &cmd, &saveptr) != 0)
     {
       goto errout;
     }
+#endif
 
   /* Handle nice */
 
@@ -916,7 +932,11 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
    * currently disabled.
    */
 
+#ifndef CONFIG_EXAMPLES_NSH_DISABLESCRIPT
   if (!cmd || !nsh_cmdenabled(vtbl))
+#else
+  if (!cmd)
+#endif
     {
       /* An empty line is not an error and an unprocessed command cannot
        * generate an error, but neither should they change the last
diff --git a/nuttx/examples/nsh/nsh_test.c b/nuttx/examples/nsh/nsh_test.c
new file mode 100644
index 000000000..a767a3ac4
--- /dev/null
+++ b/nuttx/examples/nsh/nsh_test.c
@@ -0,0 +1,446 @@
+/****************************************************************************
+ * examples/nsh/nsh_test.c
+ *
+ *   Copyright (C) 2008 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/* Test syntax:
+ *
+ * expression = simple-expression | !expression |
+ *              expression -o expression | expression -a expression
+ *
+ * simple-expression = unary-expression | binary-expression
+ *
+ * unary-expression = string-unary | file-unary
+ *
+ * string-unary = -n string | -z string
+ *
+ * file-unary = -b file | -c file | -d file | -e file | -f file |
+ *              -r file | -s file | -w file
+ *
+ * binary-expression = string-binary | numeric-binary
+ *
+ * string-binary = string = string | string == string | string != string
+ *
+ * numeric-binary = integer -eq integer | integer -ge integer |
+ *                  integer -gt integer | integer -le integer |
+ *                  integer -lt integer | integer -ne integer
+ *
+ * Note that the smallest expression consists of two strings.
+ */
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "nsh.h"
+
+#ifndef CONFIG_EXAMPLES_NSH_DISABLESCRIPT
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+#define TEST_TRUE  OK
+#define TEST_FALSE ERROR
+#define TEST_ERROR 1
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: binaryexpression
+ ****************************************************************************/
+
+static inline int binaryexpression(FAR struct nsh_vtbl_s *vtbl, char **argv)
+{
+  char *endptr;
+  long integer1;
+  long integer2;
+
+  /* STRING2 = STRING2 */
+
+  if (strcmp(argv[1], "=") == 0 || strcmp(argv[1], "==") == 0)
+    {
+      /* Return true if the strings are identical */
+
+      return strcmp(argv[0], argv[2]) == 0 ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* STRING1 != STRING2 */
+
+  if (strcmp(argv[1], "!=") == 0)
+    {
+      /* Return true if the strings are different */
+
+      return strcmp(argv[0], argv[2]) != 0 ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* The remaining operators assuming that the two values are integers */
+
+  integer1 = strtol(argv[0], &endptr, 0);
+  if (argv[0][0] == '\0' || *endptr != '\0')
+    {
+      return TEST_ERROR;
+    }
+
+  integer2 = strtol(argv[2], &endptr, 0);
+  if (argv[2][0] == '\0' || *endptr != '\0')
+    {
+      return TEST_ERROR;
+    }
+
+  /* INTEGER1 -eq INTEGER2 */
+
+  if (strcmp(argv[1], "-eq") == 0)
+    {
+      /* Return true if the strings are different */
+
+      return integer1 == integer2 ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* INTEGER1 -ge INTEGER2 */
+
+  if (strcmp(argv[1], "-ge") == 0)
+    {
+      /* Return true if the strings are different */
+
+      return integer1 >= integer2 ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* INTEGER1 -gt INTEGER2 */
+
+  if (strcmp(argv[1], "-gt") == 0)
+    {
+      /* Return true if the strings are different */
+
+      return integer1 > integer2 ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* INTEGER1 -le INTEGER2 */
+
+  if (strcmp(argv[1], "-le") == 0)
+    {
+      /* Return true if the strings are different */
+
+      return integer1 <= integer2 ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* INTEGER1 -lt INTEGER2 */
+
+  if (strcmp(argv[1], "-lt") == 0)
+    {
+      /* Return true if the strings are different */
+
+      return integer1 < integer2 ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* INTEGER1 -ne INTEGER2 */
+
+  if (strcmp(argv[1], "-ne") == 0)
+    {
+      /* Return true if the strings are different */
+
+      return integer1 != integer2 ? TEST_TRUE : TEST_FALSE;
+    }
+
+  return TEST_ERROR;
+}
+
+/****************************************************************************
+ * Name: unaryexpression
+ ****************************************************************************/
+
+static inline int unaryexpression(FAR struct nsh_vtbl_s *vtbl, char **argv)
+{
+  struct stat buf;
+  char *fullpath;
+  int   ret;
+
+  /* -n STRING */
+
+  if (strcmp(argv[0], "-n") == 0)
+    {
+      /* Return true if the length of the string is non-zero */
+
+      return strlen(argv[1]) != 0 ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* -z STRING */
+
+  if (strcmp(argv[0], "-z") == 0)
+    {
+      /* Return true if the length of the string is zero */
+
+      return strlen(argv[1]) == 0 ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* All of the remaining assume that the following argument is the
+   * path to a file.
+   */
+
+  fullpath = nsh_getfullpath(vtbl, argv[1]);
+  if (!fullpath)
+    {
+       return TEST_FALSE;
+    }
+
+  ret = stat(fullpath, &buf);
+  nsh_freefullpath(fullpath);
+
+  if (ret != 0)
+    {
+       /* The file does not exist (or another error occurred) -- return FALSE */
+
+       return TEST_FALSE;
+    }
+
+  /* -b FILE */
+
+  if (strcmp(argv[0], "-b") == 0)
+    {
+      /* Return true if the path is a block device */
+
+      return S_ISBLK(buf.st_mode) ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* -c FILE */
+
+  if (strcmp(argv[0], "-c") == 0)
+    {
+      /* Return true if the path is a character device */
+
+      return S_ISCHR(buf.st_mode) ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* -d FILE */
+
+  if (strcmp(argv[0], "-d") == 0)
+    {
+      /* Return true if the path is a directory */
+
+      return S_ISDIR(buf.st_mode) ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* -e FILE */
+
+  if (strcmp(argv[0], "-e") == 0)
+    {
+      /* Return true if the file exists */
+
+      return TEST_TRUE;
+    }
+
+  /* -f FILE */
+
+  if (strcmp(argv[0], "-f") == 0)
+    {
+      /* Return true if the path refers to a regular file */
+
+      return S_ISREG(buf.st_mode) ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* -r FILE */
+
+  if (strcmp(argv[0], "-r") == 0)
+    {
+      /* Return true if the file is readable */
+
+      return (buf.st_mode & (S_IRUSR|S_IRGRP|S_IROTH)) != 0 ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* -s FILE */
+
+  if (strcmp(argv[0], "-s") == 0)
+    {
+      /* Return true if the size of the file is greater than zero */
+
+      return buf.st_size > 0 ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* -w FILE */
+
+  if (strcmp(argv[0], "-w") == 0)
+    {
+      /* Return true if the file is write-able */
+
+      return (buf.st_mode & (S_IWUSR|S_IWGRP|S_IWOTH)) != 0 ? TEST_TRUE : TEST_FALSE;
+    }
+
+  /* Unrecognized operator */
+
+  return TEST_ERROR;
+}
+
+/****************************************************************************
+ * Name: expression
+ ****************************************************************************/
+
+static int expression(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
+{
+  int value;
+  boolean valid;
+  int i = 0;
+
+  /* Check for unary operations on expressions */
+
+  if (strcmp(argv[0], "!") == 0)
+    {
+      if (argc < 2)
+        {
+          goto errout_syntax;
+        }
+      return expression(vtbl, argc-1, &argv[1]) == TEST_TRUE ? TEST_FALSE : TEST_TRUE;
+    }
+
+  /* Check for unary operations on simple, typed arguments */
+
+  else if (argv[0][0] == '-')
+    {
+      if (argc < 2)
+        {
+          goto errout_syntax;
+        }
+      i += 2;
+      value = unaryexpression(vtbl, argv);
+    }
+
+  /* Check for binary operations on simple, typed arguments */
+
+  else
+    {
+      if (argc < 3)
+        {
+          goto errout_syntax;
+        }
+      i += 3;
+      value = binaryexpression(vtbl, argv);
+    }
+
+  /* Test if there any failure */
+
+  if (value == TEST_ERROR)
+    {
+      goto errout_syntax;
+    }
+
+  /* Is there anything after the simple expression? */
+
+  if (i < argc)
+    {
+      /* EXPRESSION -a EXPRESSION */
+
+       if (strcmp(argv[i], "-a") == 0)
+         {
+            if (!valid)
+              {
+                 goto errout_syntax;
+              }
+            else if (value != TEST_TRUE)
+              {
+                 return TEST_FALSE;
+              }
+            else
+              {
+                 i++;
+                 return expression(vtbl, argc-i, &argv[i]);
+              }
+         }
+
+       /* EXPRESSION -o EXPRESSION */
+
+       else if (strcmp(argv[i], "-o") == 0)
+         {
+           if (!valid)
+             {
+                goto errout_syntax;
+             }
+           else if (value == TEST_TRUE)
+             {
+                return TEST_TRUE;
+             }
+           else
+             {
+                i++;
+                return expression(vtbl, argc-i, &argv[i]);
+             }
+         }
+       else
+         {
+           goto errout_syntax;
+         }
+    }
+  return value; 
+
+errout_syntax:
+  nsh_output(vtbl, g_nshsyntax, "test");
+  return TEST_FALSE;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: cmd_test
+ ****************************************************************************/
+
+int cmd_test(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
+{
+  return expression(vtbl, argc-1, &argv[1]);
+}
+
+/****************************************************************************
+ * Name: cmd_lbracket
+ ****************************************************************************/
+
+int cmd_lbracket(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
+{
+  if (strcmp(argv[argc-1], "]") != 0)
+    {
+      nsh_output(vtbl, g_nshsyntax, argv[0]);
+      return ERROR;
+    }
+  else
+    {
+      return expression(vtbl, argc-2, &argv[1]);
+    }
+}
+
+#endif /* !CONFIG_EXAMPLES_NSH_DISABLESCRIPT */