http://www.shellcheck.net/
http://www.rexegg.com/regex-quantifiers.html
## r programming
http://stat545-ubc.github.io/
https://gist.github.com/lindenb/d2e45bac22cdd7772e33
http://www.nextflow.io/
http://hyperpolyglot.org/data
http://bioinfo.genotoul.fr/jvenn/example.html