apps/nshlib:  Update README.txt
@@ -540,7 +540,7 @@ o export <name> [<value>]
foo=bar
dog=poop
- The export is command is not supported by NSH unless both CONFIG_NSH_VARS=y
+ The export command is not supported by NSH unless both CONFIG_NSH_VARS=y
and CONFIG_DISABLE_ENVIRON is not set.
o free
@@ -1104,7 +1104,7 @@ o route ipv4|ipv6
o set [{+|-}{e|x|xe|ex}] [<name> <value>]
- Set the variable <name> to the sting <value> and or set NSH parser control
+ Set the variable <name> to the string <value> and or set NSH parser control
options.
For example, a variable may be set like this:
@@ -1116,7 +1116,7 @@ o set [{+|-}{e|x|xe|ex}] [<name> <value>]
foovalue
nsh>
- If CONFIG_NSH_VARS is set, the effect of the 'set' command is to set the local
+ If CONFIG_NSH_VARS is set, the effect of this 'set' command is to set the local
NSH variable. Otherwise, the group-wide environment variable will be set.
Set the 'exit on error control' and/or 'print a trace' of commands when parsing
@@ -1264,7 +1264,7 @@ o umount <dir-path>
o unset <name>
Remove the value associated with the variable <name>. This will remove
- the name-value pairt from both the NSH local variables and the group-wide
+ the name-value pair from both the NSH local variables and the group-wide
environment variables. For example:
nsh> echo $foobar
@@ -1592,6 +1592,36 @@ NSH-Specific Configuration Settings
FLASH footprint results but then also only simple environment
variables like $FOO can be used on the command line.
+ * CONFIG_NSH_VARS
+ By default, there are no internal NSH variables. NSH will use OS
+ environment variables for all variable storage. If this option, NSH
+ will also support local NSH variables. These variables are, for the
+ most part, transparent and work just like the OS environment
+ variables. The difference is that when you create new tasks, all of
+ environment variables are inherited by the created tasks. NSH local
+ variables are not.
+
+ If this option is enabled (and CONFIG_DISABLE_ENVIRON is not), then a
+ new command called 'export' is enabled. The export command works very
+ must like the set command except that is operates on environment
+ variables. When CONFIG_NSH_VARS is enabled, there are changes in the
+ behavior of certain commands
+
+ ============== =========================== ===========================
+ CMD w/o CONFIG_NSH_VARS w/CONFIG_NSH_VARS
+ ============== =========================== ===========================
+ set <a> <b> Set environment var a to b Set NSH var a to b
+ unset <a> Unsets environment var a Unsets both environment var
+ and NSH var a
+ export <a> <b> Causes an error Unsets NSH var a. Sets
+ environment var a to b.
+ export <a> Causes an error Sets environment var a to
+ NSH var b (or ""). Unsets
+ local var a.
+ env Lists all environment Lists all environment
+ variables variables
+ ============== =========================== ===========================
+
* CONFIG_NSH_QUOTE
Enables back-slash quoting of certain characters within the command.
This option is useful for the case where an NSH script is used to
