storing hex data in a file

b4e has asked for the wisdom of the Perl Monks concerning the following question:

hey again.

i need to store hexadecimal data to a file.
all i know so far is that

open (OUTPUT, ">hex.txt");
$data = 0x55; #eg
print OUTPUT $data;
close OUTPUT;
[download]

won't work, since it converts the hex value into decimal first and then stores it.
also it would be nice to store longer strings of hexadecimal data without an overflow.

thanks for your help, b4e

Comment on storing hex data in a file Download Code

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Re: storing hex data in a file by dave_the_m (Monsignor) on Aug 11, 2004 at 12:14 UTC
`print chr(0x55)` [download] PS when you say 'hex', I think you mean 'binary'. Hex is an ASCII representation of binary data, which is why people gave you answers which were correct but not what you wanted. Dave.	[reply] [d/l]
Re: storing hex data in a file by ccn (Vicar) on Aug 11, 2004 at 10:40 UTC
`print OUTPUT sprintf('0x%X', $data);` see sprintf	[reply] [d/l]
Re^2: storing hex data in a file by bgreenlee (Friar) on Aug 11, 2004 at 10:45 UTC
Or just printf, for that matter. `printf OUTPUT '0x%X', $data;` [download] brad	[reply] [d/l]
Re: storing hex data in a file by b4e (Sexton) on Aug 11, 2004 at 11:34 UTC
thanks for your replies, but that's not quite what i wanted... your code stores "Ox55" in the file, ie. the hex value 30 78 35 35. what i need is to store the hex value (eg. 55, which would be 'U' in char.)	[reply]
Re^2: storing hex data in a file by modred (Pilgrim) on Aug 11, 2004 at 11:57 UTC
You probably want to take a look at pack then. `my $x = pack("C", 0x55); print $x, "\n";` [download] works for you specific case but I don't have a good grasp of your general case to know if it will work for that.	[reply] [d/l]
Re^2: storing hex data in a file by ikegami (Patriarch) on Aug 11, 2004 at 14:46 UTC
Don't forget to use binmode() on your file handle if you're going to print out arbitrary values.	[reply]
Re: storing hex data in a file by doug (Pilgrim) on Aug 11, 2004 at 16:55 UTC
In addition to what has been said, if you're doing this on windows, don't forget binmode(). Otherwise your binary won't turn out quite right.	[reply]