u-boot script "test"
In message <[email protected]>
Quoted 11 lines
For now i got around this problem with a negative test set x
if test $x != 1 then echo "No"; else echo "Yes"; fi
with this if x is not present i get No, even in the case when x is present and set any other value (not 1)
when i do "set x 1" and run the test again i get "Yes"Thanks
Sridhar
I've experienced a similar situation. For now, I'm using U-Boot 2010.12. I want to test existence of environment var without any console output about the result, only control of conditional statement. I've found that the following provides what I need, even though it is a bit hackish.
My configuration defines CONFIG_SYS_DEVICE_NULLDEV so I can redirect stdout and hide console output during existence testing.
=> setenv stderr nulldev
=> if printenv a; then echo yes; else echo no;fi
## Error: "a" not defined
no
=> coninfo
List of available devices:
serial 80000003 SIO stdin stdout
nulldev 80000003 SIO stderr
This seems a bug, the error message goes to stdout, rather than stderr; but you decide how you think error messages should work. To work with this as it is:
=> setenv t 'setenv stdout nulldev;if printenv a; then setenv stdout serial; echo set; true; else setenv stdout serial;echo not set;false; fi' =>
=> printenv a
## Error: "a" not defined
=> run t
not set
=> setenv a 1
=> run t
set
=> run t && echo 2
set
2
=> setenv a
=> run t && echo 2
not set
=>
Notice that use of printenv does not expand the environment variable so there is never any issue with what that expands to.
If the hush shell is present, a hush variable can be used as a "parameter" to the testing script
=> setenv t 'setenv stdout nulldev;if printenv $var;then setenv stdout serial;true;else setenv stdout serial;false;fi'
=>
=> setenv b
=> if var=b;run t; then echo yes; else echo no; fi
no
=> setenv b 1
=> if var=b;run t; then echo yes; else echo no; fi
yes
=>
I hope this is helpful.
Jim