>[1S] sed '1d' Similarly sed 15q will print only the 1st 15 lines of the input and then terminate. E.g.: sed 15q file or some_command | sed 15q So, when

>[1S] sed '1d' Similarly sed 15q will print only the 1st 15 lines of the input and then terminate. E.g.: sed 15q file or some_command | sed 15q So, when put in a shell script and then called (with filename arg or using stdin): sed $1q is like a specific use of the head command [1]; it prints the first n ($1) lines of the standard input or of the filename argument given - where the value of $1 comes from the first command-line argument passed to the script. [1] In fact on earlier Unix versions I worked on (which did not have the head command (IIRC), I used to use this sed command in a script called head - similar to tail. And I also had a script called body :) to complement head and tail, with the appropriate invocation of sed. It takes two command-line arguments ($1 and $2) and prints (only) the lines in that line number range, from the input.