Hi, I am looking to insert a couple of lines in the output. The problem is that when I try "puts $fh..." the lines are inserted only at the end of the output file and not immediately, where the last line was read... I've attached a sample script to make more sense of my problem..... The output file which needs modification is attched after the script... #------------ Sample script #------------ set fh [open "...123.txt" r+] while {[gets $fh line] > 0} { set temp $line if {[string eq [lindex $temp 0] "12345"]==1} { puts $fh "one two three four five" } elseif {[string eq [lindex $temp 0] "67890"]==1} { puts $fh "six seven eight nine zero" } else { } } #--#--#--#--#-- Existing output file 12345 45678 Insert the names of the above digits... ...immediately after the number 67890 90123 ...& not at the end This is the End of line. Do not print below this!!