Hi! I'm writing a small C program to post process a huge txt file produced by a CFD software. The CFD creates a "from.txt" file, in which every line contains many parameters calculated by it. I need to copy the lines that contain the information i need to another "to.txt" files. The problem is that I don´t know how to go thru the lines of the from.txt. Once i know how to go thru them it wouldn't be that hard to write the rest of the program. I working on something like... fp=fopen(filename,"r"); while(c == getchar()); if (c == \n); ... but i have no idea how to go on... I`m a newbie in this world... hope learn a lot from you all!