note Krambambuli Thanks for the tip - I really hoped it might solve the issue, but unfortunately it does not.<br><br> For the file test.txt (TAB separated fields) being <code> a_2 2 a2 1 </code> I still get <code> $ sort -k 1,1 test.txt | cut -f 1 a2 a_2 </code> whereas when there is no second field then the result is reversed, <code> a_2 a2 </code> Looks like the problem 'survives'. <!-- Node text goes above. Div tags should contain sig only --> <br>---<br> 866330 866787