`date` command on OS X doesn't have ISO 8601 `-I` option?In a Bash script, I want to print the current datetime in ISO 8601 format (preferably UTC), and it seems that this should be as simple as date -I: http://ss64.com/bash/date.html But this doesn't seem to work on my Mac: $ date -I date: illegal option -- I usage: date [-jnu] [-d dst] [-r seconds] [-t west] [-v[+|-]val[ymwdHMS]] ... [-f fmt date | [[[mm]dd]HH]MM[[cc]yy][.ss]] [+format] And indeed, ma
