topic Re: read in file in Operating System - HP-UX

read in file

Bhoyet Orillo — Wed, 17 Jul 2002 04:30:53 GMT

Is there a way to read a specified number of bytes in
a file using a script?

Re: read in file

Steven Sim Kok Leong — Wed, 17 Jul 2002 04:41:56 GMT

Hi,

Please refer to:

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0xbe4ac4c76f92d611abdb0090277a778c,00.html

Hope this helps. Regards.

Steven Sim Kok Leong

Re: read in file

Mark Greene_1 — Wed, 17 Jul 2002 12:31:33 GMT

see the man page for dd. There are flags to specify the source file and the block size in 512-byte increments.

HTH
mark

Re: read in file

Peter Kloetgen — Wed, 17 Jul 2002 12:48:23 GMT

Hi Bhoyet,

you can use the dd- command:

dd if=/path/to/file bs=1 count=30

brings 30 bytes to standard output.

var=`dd if=/path/to/file bs=1 count=30`

gives the first 30 bytes of your file as value to the variable "var"

Allways stay on the bright side of life!

Peter

Re: read in file

Rodney Hills — Wed, 17 Jul 2002 13:24:46 GMT

Use could us "head" command with "-c" option.

head -c -n 1000 filex >first1000bytes

Would copy only the first 1000 bytes from filex.

-- Rod Hills

Re: read in file

A. Clay Stephenson — Wed, 17 Jul 2002 13:26:38 GMT

Really Perl is the scripting language of choice for this.

open F1, "$n = read(F1,$s_in,8192);
# $n - number of bytes read
# $s_in contains the data up to 8192 bytes

# now seek to offset 32768 and read again
seek(F1,32768,0);
$n = read(f1,$s_in,8192);
close F1;

You would, of course, need to add some error checking but this is the clean scripting way to do this.