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Back quoted NSH arguments now functional

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Gregory Nutt 2014-01-11 09:50:54 -06:00
parent 3bb8d74893
commit f1225b3726
1 changed files with 74 additions and 0 deletions
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Documentation/NuttShell.html
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@ -548,6 +548,37 @@ nsh>
NSH will accept multiple commands per command line with each command separated with the semi-colon character (;).
</p>
<p>
<b>Optional Syntax Extensions</b>
Because these features commit significant resources, it is disabled by default.
</p>
<ul>
<li>
<b><code>CONFIG_NSH_CMDPARMS</code></b>.
If selected, then the output from commands, from file applications, and from NSH built-in commands can be used as arguments to other commands.
The entity to be executed is identified by enclosing the command line in back quotes.
For example,
<p>
<ul><pre>
set FOO `myprogram $BAR`
</pre></ul>
<p>
Will execute the program named <code>myprogram</code> passing it the value of the environment variable <code>BAR</code>.
The value of the environment variable <code>FOO</code> is then set output of <code>myprogram</code> on <code>stdout</code>.
</li>
<li>
<b><code>CONFIG_NSH_ARGCAT</code></b>.
Support concatenation of strings with environment variables or command output. For example:
<ul><pre>
set FOO XYZ
set BAR 123
set FOOBAR ABC_${FOO}_${BAR}
</pre></ul>
would set the environment variable <code>FOO</code> to <code>XYZ</code>, <code>BAR</code> to <code>123</code> and <code>FOOBAR</code> to <code>ABC_XYZ_123</code>.
If <code>CONFIG_NSH_ARGCAT</code> is not selected, then a slightly small FLASH footprint results but then also only simple environment variables like <code>$FOO</code> can be used on the command line.
</li>
</ul>
<table width ="100%">
<tr bgcolor="#e4e4e4">
<td>
@ -2663,6 +2694,49 @@ nsh>
Default: n
</td>
</tr>
<tr>
<td valign="top"><b><code>CONFIG_NSH_CMDPARMS</code></b></td>
<td>
If selected, then the output from commands, from file applications, and from NSH built-in commands can be used as arguments to other commands.
The entity to be executed is identified by enclosing the command line in back quotes.
For example,
<ul><pre>
set FOO `myprogram $BAR
</pre></ul>
will execute the program named <code>myprogram </code> passing it the value of the environment variable <code>BAR</code>.
The value of the environment variable <code>FOO</code> is then set output of <code>myprogram</code> on <code>stdout</code>. Because this feature commits significant resources, it is disabled by default.
</td>
</tr>
<tr>
<td valign="top"><b><code>CONFIG_NSH_TMPDIR</code></b></td>
<td>
If <code>CONFIG_NSH_CMDPARMS</code> is selected, then function output will be retained
in a temporary file. In that case, this string must be provided to
specify the full path to a directory where temporary files can be
created. This would be a good application of RAM disk: To provide
temporary storage for function output.
</td>
</tr>
<tr>
<td valign="top"><b><code>CONFIG_NSH_MAXARGUMENTS</code></b></td>
<td>
The maximum number of NSH command arguments. Default: 6
</td>
</tr>
<tr>
<td valign="top"><b><code>CONFIG_NSH_ARGCAT</code></b></td>
<td>
Support concatenation of strings with environment variables or command output.
For example:
<ul><pre>
set FOO XYZ
set BAR 123
set FOOBAR ABC_${FOO}_${BAR}
</pre></ul>
would set the environment variable <code>FOO</code> to <code>XYZ</code>, <code>BAR</code> to <code>123</code> and <code>FOOBAR</code> to <code>ABC_XYZ_123</code>.
If <code>CONFIG_NSH_ARGCAT</code> is not selected, then a slightly small FLASH footprint results but then also only simple environment variables like <code>$FOO</code> can be used on the command line.
</td>
</tr>
<tr>
<td valign="top"><b><code>CONFIG_NSH_NESTDEPTH</code></b></td>
<td>