I've successfully installed optipng:
$ brew install optipng
==> Downloading https://downloads.sourceforge.net/project/optipng/OptiPNG/optipng-0.7.5/optipng-0.7.5.tar.gz
Already downloaded: /Library/Caches/Homebrew/optipng-0.7.5.tar.gz
==> Patching
patching file src/optipng/osys.c
==> ./configure --with-system-zlib --prefix=/usr/local/Cellar/optipng/0.7.5 --mandir=/usr/local/Cellar/optipng/0.7.5/share/man
==> make install
🍺 /usr/local/Cellar/optipng/0.7.5: 6 files, 156K, built in 2 seconds
but when I use the command it says the following:
$ optipng
rbenv: optipng: command not found
The `optipng' command exists in these Ruby versions:
jruby-1.7.10
jruby-1.7.11
jruby-1.7.9
If I use this path /usr/local/Cellar/optipng/0.7.5/bin/optipng it works!!
Has this something to do with rbenv? Or why isn't the optipng command global?
$ rbenv global
1.9.3-p429
I've also tried brew unlink optipng and brew link optipng -> same error!
Ok i found out that I had the image_optim_bin gem in one of my projects installed, after uninstalling this gem for all ruby versions, the command finally works!
$ gem uninstall image_optim_bin
Remove executables:
advdef, advmng, advpng, advzip, jpegoptim, jpegtran, optipng, pngcrush, pngout
in addition to the gem? [Yn]
Removing advdef
Removing advmng
Removing advpng
Removing advzip
Removing jpegoptim
Removing jpegtran
Removing optipng
Removing pngcrush
Removing pngout
Successfully uninstalled image_optim_bin-0.0.4
opened new terminal and now it works:
$ optipng
Synopsis:
optipng [options] files ...
Files:
Image files of type: PNG, BMP, GIF, PNM or TIFF
Basic options:
-?, -h, -help show the extended help
-o <level> optimization level (0-7) [default: 2]
-v run in verbose mode / show copyright and version info