1) Download usearch5.2.236 and usearch6.1
http://www.drive5.com/usearch/download.html
2) Rename files
# rename usearch5.2.236 to usearch
mv usearch5.2.236_i86linux32 usearch
# rename usearch6.1 to usearch61
mv usearch6.1.544_i86linux32 usearch61
3) Move files to /usr/local/bin/ (Ubuntu/Linux)
# set executable permissions
chmod a+x usearch usearch61
# move files to /usr/local/bin/
sudo mv usearch /usr/local/bin/
sudo mv usearch61 /usr/local/bin/