topic Re: unix command in Operating System - HP-UX

unix command

Tony Willis_1 — Wed, 21 Aug 2002 17:48:33 GMT

how to create a file for certain size, example 100mb file from unix prompt

Re: unix command

harry d brown jr — Wed, 21 Aug 2002 17:51:49 GMT

how about a file full of zeroes?

dd if=/dev/zero of=/somefilepath bs=1k count=100000

live free or die
harry

Re: unix command

harry d brown jr — Wed, 21 Aug 2002 17:53:40 GMT

/dev/zero, if it doesn't exist on your system looks like this:

# ls -l /dev/zero
crw-rw-rw- 1 bin sys 3 0x000004 Aug 13 2001 /dev/zero
#

mknod /dev/zero c 3 4

live free or die
harry

Re: unix command

H.Merijn Brand (procura — Wed, 21 Aug 2002 18:11:20 GMT

d3:/tmp 115 > rm xx
d3:/tmp 116 > ls -l xx
ls: xx: No such file or directory
d3:/tmp 117 > perl -e 'open XX,">xx";truncate XX,100*1024*1024'
d3:/tmp 118 > ls -l xx
-rw-rw-rw- 1 merijn softwr 104857600 Aug 21 21:16 xx
d3:/tmp 119 >

Re: unix command

keith persons — Wed, 21 Aug 2002 18:11:29 GMT

you can also use the prealloc(1) command to preallocate space on a disk. One caveat tho is the file will revert to actual disk space used if it isn't fully populated on the first open. i.e. prealloc filename 1000 then edit file and place only 50 bytes in file - on close it will no longer be size 1000 but 50.

hope this is clear, let me know if you're confused at all.

Re: unix command

Tom Danzig — Wed, 21 Aug 2002 19:42:19 GMT

prealloc filename 100000

Re: unix command

Tony Willis_1 — Wed, 21 Aug 2002 19:51:09 GMT

thanks for all the answers. prealloc command is the easiest solution in our situation