Removing strings after a certain character in a given text
For instance:

 rs&lt;-c("copyright @ The Society of mo","I want you to meet me @ the coffeshop")
 s&lt;-gsub("@.*","",rs)
 s
 [1] "copyright "             "I want you to meet me "


Or, if you want to keep the @ character:

 s&lt;-gsub("(@).*","\\1",rs)
 s
 [1] "copyright @"             "I want you to meet me @"


EDIT: If what you want is to remove everything from the last @ on you just have to follow this previous example with the appropriate regex. Example:

rs&lt;-c("copyright @ The Society of mo located @ my house","I want you to meet me @ the coffeshop")
s&lt;-gsub("(.*)@.*","\\1",rs)
s
[1] "copyright @ The Society of mo located " "I want you to meet me "


Given the matching we are looking for, both sub and gsub will give you the same answer.