show full path of a file

readlink -f filename gives the full absolute path. but if the file is a symlink, u'll get the final resolved name.

remove bash history under Linux

history -c 

history -w 

vim scp, etc

vimdiff a.sas scp://user@lpwcsmd1//data/b.sas 

note that / is used to separate host and path, so there are two slashes above.

git instaweb

`git instweb` can open a local http server for a git repo

imapsync all emails to one folder

use 

  --regextrans2 "s/.*/folder_on_Bmail\/$&/"

promise in R
#define PROMSXP 5 /* promises: [un]evaluated closure arguments */  
reference
pryr
and see force in R

see the version number of mac on command line

$ sw_vers

ProductName: Mac OS X

ProductVersion: 10.9.5

BuildVersion: 13F34