Stata itself will tell you. 
. search view source
Keyword search
        Keywords:  view source
          Search:  (1) Official help files, FAQs, Examples, SJs, and
STBs
Search of official help files, FAQs, Examples, SJs, and STBs
[P]     viewsource  . . . . . . . . . . . . . . . . . . . . . View
source code
        (help viewsource)
[M-1]   source  . . . . . . . . . . . . . . . . . . .  Viewing the
source code
        (help [M-1] source)
Book    . . . . . . . . . . . . . . . . . . . . . . .  Thirty-three
Stata Tips
        . . . . . . . . . . . . . . . . . . . . H. Joseph Newton and N.
J. Cox
        http://www.stata.com/bookstore/tips.html
FAQ     How can I load, write or view dBASE, Excel or Access files using
odbc?
        . . . . . . . . . . . . . . . . . .  UCLA Academic Technology
Services
        7/08    http://www.ats.ucla.edu/stat/stata/faq/odbc.htm
SJ-6-1  pr0022  . . . . . . . . . . . Stata tip 30: May the source be
with you
        . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  N.
J. Cox
        Q1/06   SJ 6(1):149--150                                 (no
commands)
        tip for using viewsource to locate and view source
        code or text files
Nick 
[email protected] 
Miranda Kim
Out of interest, how can one view the source code for the command as you
suggest?
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