Maiar's Vault

mysql get first and last day of the month mysql> select SUBDATE('2009-08-20',DAYOFMONTH('2009-08-20')-1),DAYOFMONTH('2009-08-20'),LAST_DAY('2009-08-20') from dual; +--------------------------------------------------+--------------------------+------------------------+ | SUBDATE('2009-08-20',DAYOFMONTH('2009-08-20')-1) | DAYOFMONTH('2009-08-20') | LAST_DAY('2009-08-20') | +--------------------------------------------------+--------------------------+------------------------+ | 2009-08-01 | 20 | 2009-08-31 | +--------------------------------------------------+--------------------------+------------------------+ 1 row in set (0.00 sec)

This will return the first day of the month '2009-08-01' in mysql select SUBDATE('2009-08-31',DAYOFMONTH('2009-08-31')-1) from dual;

In perl to test if a directory exists use -d "somedir" example: if(-d "/home/username") { print "User directory exists\n"; }

10 Most Common Mistakes in Online Advertising This is interesting

Apparently the Morin family motto. "lucent in tenebris" which is latin for "light in darkness"

Testing if a variable exists in ruby is pretty easy. irb(main):001:0> defined? variablename This will return if it's defined but not just variables but a few things "local-variable" "global-variable" nil # (undefined) "method" "super" "yield"

for r in `git rev-list master...master-fubar --since="8:00" --before="12:00" --no-merges`; do git revert --no-edit -s $r; done

The default pid file location for a hadoop cluster as of 19.1 and 19.2, might also be the same for earlier versions of hadoop /tmp/hadoop-[USERNAME]-[NODETYPE].pid I usually run hadoop as root so here is an example of the default pid file for a datanode /tmp/hadoop-root-datanode.pid NODETYPES namenode datanode tasktracker