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Old 01-07-2005, 07:00 AM   #1
zameer_india
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Location: hyderabad
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want full description of "echo num > / path/...."


Hi All......


could any body explain me what happens with the following commands ......

echo 0 > / proc/xxxx
echo 1 > / proc/yyyy
echo 2 > / proc/zzzz
echo 3 > / proc/aaaa


form the above four lines i understood that

"echo" is for " Display Purpose/OP"
0,1,2,3.... is this are IRQ Numbers ?
what is the function of " > "?

I think it is silly one for U ... not for me.... any help would be appreciate....

thnx in Advance...

zameer ahmed syed
 
Old 01-07-2005, 07:09 AM   #2
MasterC
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Location: Salt Lake City, UT - USA
Distribution: Gentoo ; LFS ; Kubuntu
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Re: want full description of "echo num > / path/...."

Quote:
Originally posted by zameer_india
Hi All......


could any body explain me what happens with the following commands ......

echo 0 > / proc/xxxx
echo 1 > / proc/yyyy
echo 2 > / proc/zzzz
echo 3 > / proc/aaaa


form the above four lines i understood that

"echo" is for " Display Purpose/OP"
0,1,2,3.... is this are IRQ Numbers ?
what is the function of " > "?

I think it is silly one for U ... not for me.... any help would be appreciate....

thnx in Advance...

zameer ahmed syed
echoing can be used for a lot of things, but basically what the above is doing:

echo 1 > /proc/whatever
Is sending the 1 to that file, to replace anything in it. Usually 1's turn things on, 0 turns them off.

The > is the thing to note.
If you were to:
echo 1 /proc/whatever
You'd get a 1 on your screen followed probably by a command not found or something similar, and the 1 would not be sent to /proc/whatever. The > tells echo not to send it to stdout (the terminal in this case) but rather to a file.

HTH

Cool
 
Old 01-07-2005, 07:54 AM   #3
zameer_india
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Registered: Sep 2004
Location: hyderabad
Posts: 210

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Thanx MasterC for Ur kind and Descriptive Reply..
Well and Understandable Explanation... but one thing i am not understand about numbers ....
If I used 1 , 0 , 2 ,l... i got the same result..... i am not able to differentiate between these numbers..... U said that 1 is for turned ON...
0 is for turned OFF...
I used 0,1and even 2 also ..... didn't get any errors...same result for all..... little bit hanging here that what is turn ON and turn OFF... and about these numbers..
i am requesting U some more explantion about this issue.....

thnx ...
zameer ahmed syed
 
Old 01-08-2005, 03:45 AM   #4
MasterC
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Registered: Mar 2002
Location: Salt Lake City, UT - USA
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The numbers are dependant upon whatever process you are applying them to. My suggestion of 1's being 'on' and 0's being 'off' might not always hold true, you'd be best off researching the process you are wanting to apply the numbers to. The number could also be for how many processes to start, or how many subdirectories to recurse...

Cool
 
Old 01-08-2005, 04:04 AM   #5
zameer_india
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Registered: Sep 2004
Location: hyderabad
Posts: 210

Original Poster
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thanx MasterC...... U done a gr8 help for me....
 
Old 01-08-2005, 04:10 AM   #6
MasterC
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Registered: Mar 2002
Location: Salt Lake City, UT - USA
Distribution: Gentoo ; LFS ; Kubuntu
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No problem, glad I could help.

Cool
 
  


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