As the latest successor to locate, plocate produces some of the quickest search results possible on any system.
Real estate agents sometimes say that the key to success is location, location, location. This saying might almost summarize the history of the
locate command  and its various successors, particularly
mlocate  and
plocate . As a replacement for
find, all three commands use a database solution to reduce search time. While all three share many of the same options,
plocate is widely considered the most efficient choice.
Slightly different versions of
locate are available in the BSD and GNU findutils, but you can also find
plocate as separate commands. Because the number of choices can be confusing, a history seems in order. First released in 1982,
locate uses a database that can be read by any user. If regular expressions are not used, it displays every instance of the string entered on the system, which is inconvenient if the string is common. However,
locate‘s most serious limitation is that the database has to be updated manually. Largely because of these problems – especially the need for manual updates –
locate was succeeded briefly by
slocate (secure locate)  until replaced in 2006 by
mlocate (merging locate). Both
mlocate are an improvement over
locate in that they contain the utility
updatedb  to update databases, speeding up the process by only searching for files and directories where the
ctime has changed. Also, both
mlocate show only the files that the current user has access to, thereby improving security, and they allow regular expressions to be used without a specific option. Written by Miloslav Trmac while he participated in the Google Summer of Code,
mlocate became the preferred version until 2020, although it seems to have gone through periods of being unmaintained.
Named for the posting lists that inspired it,
plocate was written to be a drop-in replacement for
mlocate. While it can still use
updatedb to create its database,
plocate can also use the
plocate-build utility  to create an index when a root user is logged in. Unlike
mlocate, when multiple strings are searched,
plocate returns only the files that match all the search strings, rather than any file that matches even one string. Another difference from
plocate is compatible with systemd and SELinux. Instead of scanning every entry one at a time,
plocate scans trigrams (i.e., combinations of three bytes at a time) to increase search speeds. Although specifically designed for solid state drives (SSDs), on older hard drives,
plocate can gain further speed by using the
io_uring Asynchronous I/O (AIO) framework introduced in the Linux 5.1 kernel in March 2019 . As its main limitation,
plocate‘s benefits may be lost when searching for strings shorter than three bytes, for non-UTF-8 file names, or for regular expressions with numerous hits. Usually, its enhancements mean that
plocate can find two files out of 27 million in .008 milliseconds, while
mlocate takes 20.118 milliseconds for the same operation . Even though
mlocate are still available, in most circumstances,
plocate should be the preferred variant.
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