diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 01f57c4..f97929b 100644
*** a/doc/src/sgml/ref/psql-ref.sgml
--- b/doc/src/sgml/ref/psql-ref.sgml
*************** lo_import 152801
*** 2242,2247 ****
--- 2242,2265 ----
  
  
        <varlistentry>
+         <term><literal>\setenv [ <replaceable class="parameter">name</replaceable> [ <replaceable class="parameter">value</replaceable> ] ]</literal></term>
+ 
+         <listitem>
+         <para>
+         Sets the environment variable <replaceable
+         class="parameter">name</replaceable> to <replaceable
+         class="parameter">value</replaceable>, or if the
+         <replaceable class="parameter">value</replaceable> is
+         not supplied, unsets the environment variable. Example:
+ <programlisting>
+ testdb=&gt; <userinput>\setenv PAGER less</userinput>
+ testdb=&gt; <userinput>\setenv LESS -imx4F</userinput>
+ </programlisting>
+         </para>
+         </listitem>
+       </varlistentry>
+ 
+       <varlistentry>
          <term><literal>\sf[+] <replaceable class="parameter">function_description</> </literal></term>
  
          <listitem>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 9cc73be..e4b4eaa 100644
*** a/src/bin/psql/command.c
--- b/src/bin/psql/command.c
*************** exec_command(const char *cmd,
*** 1110,1115 ****
--- 1110,1160 ----
  		free(opt0);
  	}
  
+ 
+ 	/* \setenv -- set environment command */
+ 	else if (strcmp(cmd, "setenv") == 0)
+ 	{
+ 		char	   *envvar = psql_scan_slash_option(scan_state,
+ 												  OT_NORMAL, NULL, false);
+ 		char	   *envval = psql_scan_slash_option(scan_state,
+ 												  OT_NORMAL, NULL, false);
+ 
+ 		if (!envvar)
+ 		{
+ 			psql_error("\\%s: missing required argument\n", cmd);
+ 			success = false;
+ 		}
+ 		else if (strchr(envvar,'=') != NULL)
+ 		{
+ 			psql_error("\\%s: environment variable name must not contain '='\n",
+ 					   cmd);
+ 			success = false;
+ 		}
+ 		else if (!envval)
+ 		{
+ 			/* No argument - unset the environment variable */
+ 			unsetenv(envvar);
+ 			success = true;
+ 		}
+ 		else
+ 		{
+ 			/* Set variable to the value of the next argument */
+ 			int         len = strlen(envvar) + strlen(envval) + 1;
+ 			char	   *newval = pg_malloc(len + 1);
+ 
+ 			snprintf(newval, len+1, "%s=%s", envvar, envval);
+ 			putenv(newval);
+ 			success = true;
+ 			/*
+ 			 * Do not free newval here, it will screw up the environment
+ 			 * if you do. See putenv man page for details. That means we
+ 			 * leak a bit of memory here, but not enough to worry about.
+ 			 */
+ 		}
+ 		free(envvar);
+ 		free(envval);
+ 	}
+ 
  	/* \sf -- show a function's source code */
  	else if (strcmp(cmd, "sf") == 0 || strcmp(cmd, "sf+") == 0)
  	{
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 4649e94..13d8bf6 100644
*** a/src/bin/psql/help.c
--- b/src/bin/psql/help.c
*************** slashUsage(unsigned short int pager)
*** 158,164 ****
  {
  	FILE	   *output;
  
! 	output = PageOutput(93, pager);
  
  	/* if you add/remove a line here, change the row count above */
  
--- 158,164 ----
  {
  	FILE	   *output;
  
! 	output = PageOutput(94, pager);
  
  	/* if you add/remove a line here, change the row count above */
  
*************** slashUsage(unsigned short int pager)
*** 257,262 ****
--- 257,263 ----
  
  	fprintf(output, _("Operating System\n"));
  	fprintf(output, _("  \\cd [DIR]              change the current working directory\n"));
+ 	fprintf(output, _("  \\setenv NAME [VALUE]   set or unset environment variable\n"));
  	fprintf(output, _("  \\timing [on|off]       toggle timing of commands (currently %s)\n"),
  			ON(pset.timing));
  	fprintf(output, _("  \\! [COMMAND]           execute command in shell or start interactive shell\n"));