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Diffstat (limited to 'README')
| -rw-r--r-- | README | 48 |
1 files changed, 45 insertions, 3 deletions
@@ -2048,6 +2048,48 @@ Please note that changes to some configuration parameters may take only effect after the next boot (yes, that's just like Windoze :-). +Command Line Parsing: +===================== + +There are two different command line parsers available with U-Boot: +the old "simple" one, and the much more pwerful "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 af variables as arguments), any failing + command will cause "run" to terminate, i. e. the remaining + variables are not executed. + Note for Redundant Ethernet Interfaces: ======================================= @@ -2563,9 +2605,9 @@ Minicom warning: ================ Over time, many people have reported problems when trying to used the -"minicom" terminal emulation program for serial download. I (wd) -consider minicom to be broken, and recommend not to use it. Under -Unix, I recommend to use CKermit for general purpose use (and +"minicom" terminal emulation program for serial download. I (wd) +consider minicom to be broken, and recommend not to use it. Under +Unix, I recommend to use C-Kermit for general purpose use (and especially for kermit binary protocol download ("loadb" command), and use "cu" for S-Record download ("loads" command). |