esearch is the emerge search with index, you will need to run eupdatedb to update its index database, it parses ebuilds, that would take around 10 minutes, mine took 10 minutes and 41 seconds , not really fast for creating an index:


$ sudo eupdatedb
 * indexing: 0 ebuilds to go
 * esearch-index generated in 10 minute(s) and 41 second(s)
 * indexed 17352 ebuilds
 * size of esearch-index: 2875 kB

The consequent update is much faster, only took about 1 minute and 38 seconds.

A sample output, which looks just like emerge -s:


$ esearch esearch
[ Results for search key : esearch ]
[ Applications found : 2 ]

*  app-portage/esearch
      Latest version available: 1.3-r1
      Latest version installed: 1.3-r1
      Size of downloaded files: 18 kB
      Homepage:    http://david-peter.de/esearch.html
      Description: Replacement for 'emerge --search' with search-index
      License:     GPL-2

*  app-vim/multiplesearch
      Latest version available: 1.3
      Latest version installed: [ Not Installed ]
      Size of downloaded files: 6 kB
      Homepage:    http://www.vim.org/scripts/script.php?script_id=479
      Description: vim plugin: allows multiple highlighted searches
      License:     vim

It can search in description, in installed or not in installed packages, by filepath, by ebuild, etc. You can also customize the output format.

Here is a quick tests of the speed of emerge, esearch, and eix:


$ time emerge -s esearch > /dev/null

real    0m3.598s
user    0m3.332s
sys     0m0.181s

$ time esearch esearch > /dev/null

real    0m0.168s
user    0m0.139s
sys     0m0.026s

$ time eix esearch > /dev/null

real    0m0.095s
user    0m0.084s
sys     0m0.011s

eix is still the best in my opinion, the fastest, and with many searching options. Never the less, I believe it still has its place in Gentoo world. The first entry in its Changelog was version 0.3.1 on 2003-09-17, that was more than a decade ago.

esearch is written by David Peter, Brian Dolbec, Paul Varner, et al., under the GPLv2, current version 1.3 (2012-11-03) via app-portage/esearch-1.3-r1.