How search a list of numbers from a file

Hi Guys!

I have two input files. I want to search each of the numbers (studentid) on inputfile1 from inputfile2 and print the studentid and section that are listed from inputfile1. See the desired output below.

inputfile1.txt:

studentid
261054689
266605695
269826642
264966513
267759044

inputfile2.txt:

studentid,class
269356045,100
264679884,100
266565812,440
261167017,440
274742653,100
261054689,440
268487469,440
266747948,100
261056733,440
269466302,100
269826642,430
264161985,100
264751425,440
267759044,100
267636636,100
268619810,100
269610516,430
261105733,440
264966513,100
267827396,440
266288625,100
266605695,100
266122563,390
266665542,440
267704403,440
268251798,100

Desired Output:

261054689,440
266605695,100
269826642,430
264966513,100
267759044,100

Thanks in advance.

Br,
pinpe

cut the header of inputfile1, then

grep -f inputfile1 inputfile2

in case grep -f is not available ..

$ xargs<file1|sed 's, ,|,g;s,^,egrep \",g;s,$,\" file2,g' | sh