Stata 15 help for which
[R] which -- Display location and version of an ado-file
which fname[.ftype] [, all]
which looks for file fname.ftype along the S_ADO path. If Stata finds
the file, which displays the full path and filename, along with, if the
file is text, all lines in the file that begin with "*!" in the first
column. If Stata cannot find the file, which issues the message "file
not found along ado-path" and sets the return code to 111. ftype must be
a file type for which Stata usually looks along the ado-path to find.
Allowable ftypes are
.ado, .class, .dlg, idlg, .sthlp, .ihlp, .hlp, .key, .maint, .mata,
.mlib, .mo, .mnu, .plugin, .scheme, .stbcal, and .style
If ftype is omitted, which assumes .ado. When searching for .ado files,
if Stata cannot find the file, Stata then checks to see if fname is a
built-in Stata command, allowing for valid abbreviations. If it is, the
message "built-in command" is displayed; if not, the message "command not
found as either built-in or ado-file" is displayed and the return code is
set to 111.
For information on internal version control, see [P] version.
all forces which to report the location of all files matching the
fname.ftype found along the search path. The default is to report
just the first one found.
The which command displays the path for filename.ado and any lines in the
code that begin with "*!".
. which test
*! version 2.3.4 14apr2016
If we type which command, where command is a built-in command rather than
an ado-file, Stata responds with
. which summarize
built-in command: summarize
If command was neither a built-in command nor an ado-file, Stata would
. which junk
command junk not found as either built-in or ado-file