Is there a way to copy the first line in a text file to the end of every line? - could include copying line 1 to the end of line 1 if it simplifies things. I have: __1 2 3 I want: 1 2__1 3__1 or  1__1 2__1 3__1It has to be easily modified to handle multiple files.Any suggestions?Big thanks.
Looking for way to copy first line of text file to end of every line
text processing