On 17 July 2013 16:32, Christian Neukirchen <chneukirc...@gmail.com> wrote: > Calvin Morrison <mutanttur...@gmail.com> writes: > >> Hi guys, >> >> I came up with a utility[0] that i think could be useful, and I sent >> it to the moreutils page, but maybe it might fit better here. All it >> does is give a count of files in a directory. >> >> I was sick of ls | wc -l being so damned slow on large directories, so >> I thought a more direct solution would be better. >> >> calvin@ecoli:~/big_folder> time ls file2v1dir/ | wc -l >> 687560 >> >> real 0m7.798s >> user 0m7.317s >> sys 0m0.700s >> >> calvin@ecoli:~/big_folder> time ~/bin/dc file2v1dir/ >> 687560 >> >> real 0m0.138s >> user 0m0.057s >> sys 0m0.081s >> >> What do you think? >> Calvin > > What's the bottle neck here?
Looking up the filenames and reading them, printing them to standard out and then wc parsing for all the \n characters. > (Or is your dc only faster because the directory index is in cache now...) No that's not why: calvin@ecoli:~/big_folder> ls 2v1 | wc -l 687560 real 0m7.678s user 0m7.313s sys 0m0.579s calvin@ecoli:~/big_folder> time dc 2v1 687560 real 0m0.138s user 0m0.055s sys 0m0.082s calvin@ecoli:~/big_folder> time ls 2v1 | wc -l 687560 real 0m7.672s user 0m7.310s sys 0m0.580s > -- > Christian Neukirchen <chneukirc...@gmail.com> http://chneukirchen.org > >
