a fast way to repeat output a byte

tr '\0' '\377' < /dev/zero|dd count=$((<bytes>/512))
the speed is about 500MB/s on my machine. i think it's fast enough to output not too many bytes. while a C program may output 1GB per sencond on my machine. if the size is not the power of 512,you may change the bs and count in dd.
Sample Output
$ time tr '\0' '\377' < /dev/zero|dd count=$((24*1024*2)) > /dev/null
49152+0 records in
49152+0 records out
25165824 bytes (25 MB) copied, 0.0491487 s, 512 MB/s
tr '\0' '\377' < /dev/zero  0.02s user 0.02s system 82% cpu 0.053 total
dd count=$((24*1024*2)) > /dev/null  0.01s user 0.03s system 76% cpu 0.052 total

By: cfy
2011-04-05 14:26:02

1 Alternatives + Submit Alt

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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