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+.. SPDX-License-Identifier: GPL-2.0+
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+
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+Command-line Parsing
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+====================
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+
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+The command line is available in U-Boot proper, enabled by CONFIG_CMDLINE which
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+is on by default. It is not enabled in SPL.
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+
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+There are two different command-line parsers available with U-Boot:
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+the old "simple" one, and the much more powerful "hush" shell:
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+
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+Simple command-line parser
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+--------------------------
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+
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+This takes very little code space and offers only basic features:
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+
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+- supports environment variables (through setenv / saveenv commands)
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+- several commands on one line, separated by ';'
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+- variable substitution using "... ${name} ..." syntax
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+- special characters ('$', ';') can be escaped by prefixing with '\',
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+ for example::
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+
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+ setenv bootcmd bootm \${address}
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+
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+- You can also escape text by enclosing in single apostrophes, for example::
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+
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+ setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
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+
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+Hush shell
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+----------
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+
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+This is similar to Bourne shell, with control structures like:
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+
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+- `if`... `then` ... `else`... `fi`
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+- `for`... `do` ... `done`
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+- `while` ... `do` ... `done`
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+- `until` ... `do` ... `done`
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+
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+Hush supports environment ("global") variables (through setenv / saveenv
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+commands) and local shell variables (through standard shell syntax
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+`name=value`); only environment variables can be used with the "run" command
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+
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+The Hush shell is enabled with `CONFIG_HUSH_PARSER`.
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+
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+General rules
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+-------------
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+
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+#. If a command line (or an environment variable executed by a "run"
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+ command) contains several commands separated by semicolon, and
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+ one of these commands fails, then the remaining commands will be
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+ executed anyway.
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+
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+#. If you execute several variables with one call to run (i. e.
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+ calling run with a list of variables as arguments), any failing
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+ command will cause "run" to terminate, i. e. the remaining
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+ variables are not executed.
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