UBootCmdGroupEnvironment < DULG

%SECTION0{name=UBootCmdGroupEnvironment}% Environment Variables Commands

%SECTION1{name=UBootCmdPrintenv}% printenv- print environment variables

%INCLUDE{DULGData_%BOARD%.UBootPrintenvHelp}%

The =printenv= command prints one, several or all variables
of the U-Boot environment. When arguments are given, these are
interpreted as the names of environment variables which will be
printed with their values:

%INCLUDE{DULGData_%BOARD%.UBootPrintenvWithArgs}%

Without arguments, =printenv= prints all a list with
all variables in the environment and their values, plus some
statistics about the current usage and the total size of the memory
available for the environment.

%INCLUDE{DULGData_%BOARD%.UBootPrintenvNoArgs}%

%SECTION1{name=UBootCmdSaveenv}% saveenv - save environment variables to persistent storage

%INCLUDE{DULGData_%BOARD%.UBootSaveenvHelp}%

All changes you make to the U-Boot environment are made in RAM only.
They are lost as soon as you reboot the system. If you want to make
your changes permanent you have to use the =saveenv=
command to write a copy of the environment settings to persistent
storage, from where they are automatically loaded during startup:

%INCLUDE{DULGData_%BOARD%.UBootSaveenv}%


%SECTION1{name=UBootCmdSetenv}%   setenv  - set environment variables

%INCLUDE{DULGData_%BOARD%.UBootSetenvHelp}%

To modify the U-Boot environment you have to use the
=setenv= command. When called with exactly one
argument, it will delete any variable of that name from U-Boot's
environment, if such a variable exists. Any storage occupied for such
a variable will be automatically reclaimed:

%INCLUDE{DULGData_%BOARD%.UBootSetenvDelete}%

When called with more arguments, the first one will again be the name
of the variable, and all following arguments will (concatenated by
single space characters) form the value that gets stored for this
variable. New variables will be automatically created, existing ones
overwritten.

%INCLUDE{DULGData_%BOARD%.UBootSetenvSet}%

Remember standard shell quoting rules when the value of a variable
shall contain characters that have a special meaning to the command
line parser (like the =$= character that is used
for variable substitution or the semicolon which separates commands).
Use the backslash (=\=) character to escape such
special characters, or enclose the whole phrase in apstrophes (='=).
Use ="${name}"= for variable expansion
(see %REF{type=Section,topic=CommandLineParsing,name=CommandLineParsing}% for details).

%INCLUDE{DULGData_%BOARD%.UBootSetenvQuote}%

%T% There is no restriction on the characters that can be used in a
variable name except the restrictions imposed by the command line
parser (like using backslash for quoting, space and tab characters to
separate arguments, or semicolon and newline to separate commands).
Even strange input like "=-/|()+=" is a perfectly
legal variable name in U-Boot.

%X% A common mistake is to write
<verbatim>
setenv name=value
</verbatim>

instead of

<verbatim>
setenv name value
</verbatim>

There will be no error message, which lets you believe everything went
OK, but it didn't: instead of setting the variable _name_ to the value
_value_ you tried to delete a variable with the name _name<nop>=value_
- this is probably not what you intended! Always remember that name
and value have to be separated by space and/or tab characters!

%SECTION1{name=UBootCmdRun}% run     - run commands in an environment variable

%INCLUDE{DULGData_%BOARD%.UBootRunHelp}%

You can use U-Boot environment variables to store commands and even
sequences of commands. To execute such a command, you use the
=run= command:

%INCLUDE{DULGData_%BOARD%.UBootRun}%

You can call =run= with several variables as
arguments, in which case these commands will be executed in sequence:

%INCLUDE{DULGData_%BOARD%.UBootRunSequence}%

%T% If a U-Boot variable contains several commands (separated by
semicolon), and one of these commands fails when you "run" this
variable, the remaining commands _will be executed anyway_.

%T% If you execute several variables with one call to
=run=, any failing command will cause "run" to
terminate, i. e. the remaining variables are _not_
executed.

%SECTION1{name=UBootCmdBootd}% bootd   - boot default, i.e., run 'bootcmd'

%INCLUDE{DULGData_%BOARD%.UBootBootdHelp}%

The =bootd= (short: =boot=) executes
the default boot command, i. e. what happens when you don't interrupt
the initial countdown. This is a synonym for the =run bootcmd=
command.
5.9.5. Download Commands		1. Abstract		5.9.7. Flattened Device Tree support
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