On Wed, Jun 20, 2018 at 08:20:16PM +0200, Maximilian Pichler wrote: > On Wed, Jun 20, 2018 at 7:17 PM, Tomasz Rola <rto...@ceti.pl> wrote: > > But seriously: man sh. > > Are you saying there is a shell built-in that does this? If so, which one?
=> (591 13): cat nread #!/bin/sh # nread n - read up to n bytes from stdio, put them on to stdout N=$1 dd bs=512 count=$((N / 512)) dd bs=1 count=$((N % 512)) => (591 14): md5sum <nread 9c6d3e6aa2b11f6351290fc4f770bf44 - => (591 15): chmod a+x nread => (591 16): cat HUGE | /usr/bin/time ./nread 1234567 | wc -c 2411+0 records in 2411+0 records out 1234432 bytes (1.2 MB) copied, 0.0122527 s, 101 MB/s 135+0 records in 135+0 records out 135 bytes (135 B) copied, 0.000620305 s, 218 kB/s 0.00user 0.01system 0:00.02elapsed 57%CPU (0avgtext+0avgdata 768maxresident)k 0inputs+0outputs (0major+731minor)pagefaults 0swaps 1234567 Total time is well below 1s. If you want faster, then you have to write it in C or assembly. -- Regards, Tomasz Rola -- ** A C programmer asked whether computer had Buddha's nature. ** ** As the answer, master did "rm -rif" on the programmer's home ** ** directory. And then the C programmer became enlightened... ** ** ** ** Tomasz Rola mailto:tomasz_r...@bigfoot.com **
