Commit 7a4ff7c4 authored by Simon Glass's avatar Simon Glass Committed by Tom Rini
Browse files

doc: Convert command-line info to rST



Take this part of the README and put it into rST format.
Signed-off-by: Simon Glass's avatarSimon Glass <sjg@chromium.org>
parent 5a94546e
......@@ -3510,47 +3510,6 @@ The signature of the callback functions is:
The return value is 0 if the variable change is accepted and 1 otherwise.
Command Line Parsing:
=====================
There are two different command line parsers available with U-Boot:
the old "simple" one, and the much more powerful "hush" shell:
Old, simple command line parser:
--------------------------------
- supports environment variables (through setenv / saveenv commands)
- several commands on one line, separated by ';'
- variable substitution using "... ${name} ..." syntax
- special characters ('$', ';') can be escaped by prefixing with '\',
for example:
setenv bootcmd bootm \${address}
- You can also escape text by enclosing in single apostrophes, for example:
setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
Hush shell:
-----------
- similar to Bourne shell, with control structures like
if...then...else...fi, for...do...done; while...do...done,
until...do...done, ...
- supports environment ("global") variables (through setenv / saveenv
commands) and local shell variables (through standard shell syntax
"name=value"); only environment variables can be used with "run"
command
General rules:
--------------
(1) If a command line (or an environment variable executed by a "run"
command) contains several commands separated by semicolon, and
one of these commands fails, then the remaining commands will be
executed anyway.
(2) If you execute several variables with one call to run (i. e.
calling run with a list of variables as arguments), any failing
command will cause "run" to terminate, i. e. the remaining
variables are not executed.
Note for Redundant Ethernet Interfaces:
=======================================
......
.. SPDX-License-Identifier: GPL-2.0+
Command-line Parsing
====================
The command line is available in U-Boot proper, enabled by CONFIG_CMDLINE which
is on by default. It is not enabled in SPL.
There are two different command-line parsers available with U-Boot:
the old "simple" one, and the much more powerful "hush" shell:
Simple command-line parser
--------------------------
This takes very little code space and offers only basic features:
- supports environment variables (through setenv / saveenv commands)
- several commands on one line, separated by ';'
- variable substitution using "... ${name} ..." syntax
- special characters ('$', ';') can be escaped by prefixing with '\',
for example::
setenv bootcmd bootm \${address}
- You can also escape text by enclosing in single apostrophes, for example::
setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
Hush shell
----------
This is similar to Bourne shell, with control structures like:
- `if`... `then` ... `else`... `fi`
- `for`... `do` ... `done`
- `while` ... `do` ... `done`
- `until` ... `do` ... `done`
Hush supports environment ("global") variables (through setenv / saveenv
commands) and local shell variables (through standard shell syntax
`name=value`); only environment variables can be used with the "run" command
The Hush shell is enabled with `CONFIG_HUSH_PARSER`.
General rules
-------------
#. If a command line (or an environment variable executed by a "run"
command) contains several commands separated by semicolon, and
one of these commands fails, then the remaining commands will be
executed anyway.
#. If you execute several variables with one call to run (i. e.
calling run with a list of variables as arguments), any failing
command will cause "run" to terminate, i. e. the remaining
variables are not executed.
......@@ -9,6 +9,7 @@ Use U-Boot
fit
netconsole
partitions
cmdline
Shell commands
--------------
......
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