walk and sor

This repository contains walk and sor, two utility programs that collectively replace find. walk recursively walks the directories specified on the command line (or the current directory, if none is specified), printing each file path. sor (“shell or”) reads file paths from standard input; for each path, it evaluates its arguments as Bash snippets, passing the path as an argument to each and printing the path if any snippet exits with status 0. For example, instead of saying

find . -type f -name \*foo\*

you can say

walk | grep foo | sor 'test -f'

If your filenames might contain newlines, you can say

walk -0 | grep -z foo | sor -0 'test -f'


By avoiding syscalls, walk achieves substantially better performance than find. A microbenchmark –

$ time find /usr >/dev/null real 0m3.542s user 0m0.880s sys 0m2.646s $ time walk /usr >/dev/null real 0m2.311s user 0m0.370s sys 0m1.926s

– shows walk executing nearly 40% faster on a local file system with a hot cache. Performance on network file systems should be even better. On the other hand, find implements its predicates in-process, making them orders of magnitude faster than sor:

$ time find /usr -type f >/dev/null real 0m3.464s user 0m0.831s sys 0m2.615s $ time walk /usr | sor 'test -f' >/dev/null real 7m40.127s user 1m47.818s sys 2m48.595s


walk and sor were originally written for Plan 9 from Bell Labs by Dan Cross. The original source is available.


This is not an official Google product.