There are several ways to do this. One of them is to define variable names from PROC CONTENTSor dictionary.columnsand create rename commands.
data have;
input x1-x4;
datalines;
1 2 3 4
5 6 7 8
;;;;
run;
%macro rename(var=,newvar=);
rename &var.=&newvar.;
%mend rename;
data my_vars; *the list of your new variable names, and their variable number;
length varname $10;
input varnum varname $;
datalines;
1 FirstVar
2 SecondVar
3 ThirdVar
4 FourthVar
;;;;
run;
proc sql; *Create a list of macro calls to the rename macro from joining dictionary.columns with your data. ;
* Dictionary.columns is like proc contents.;
select cats('%rename(var=',name,',newvar=',varname,')')
into :renamelist separated by ' '
from dictionary.columns C, my_vars M
where C.memname='HAVE' and C.libname='WORK'
and C.varnum=M.varnum;
quit;
proc datasets;
modify have;
&renamelist; *use the calls;
quit;
/ _INFILE_ ( ). . , , , .
data have;
input x1-x4;
datalines;
1 2 3 4
5 6 7 8
;;;;
run;
data want;
set have;
infile datalines truncover; *or it will go to next line and EOF prematurely;
input @1 @@; *Reinitialize to the start of the line or it will eventually EOF early;
_infile_=catx(' ',of _all_); *put to input stream as space delimited - if your data has spaces you need something else;
input y1-y4 @@; *input as space delimited;
put _all_; *just checking our work, for debugging;
datalines; *dummy datalines (could use a dummy filename as well);
;;;;
run;