Since several years, I needed time to time a filter which can remove conditionnally a newline character. Now I have the solution as in this example: test> cat in.txt | sed '/SCENE.*[^\.]$/N;s/\n */ /' This command will join from the in.txt output the lines which contain the word "SCENE" and don't end with a dot character ("."). test> cat in.txt ACTE V SCENE IV. -- ELISE, MARIANE, FROSINE, HARPAGON, VALERE, MAITRE JACQUES, LE COMMISSAIRE, SON CLERC. SCENE II. -- MAITRE JACQUES, HARPAGON, LE COMMISSAIRE, SON CLERC. SCENE V. -- ANSELME, HARPAGON, ELISE, MARIANE, FROSINE, VALERE, MAITRE JACQUES, LE COMMISSAIRE, SON CLERC. Thanks to Google who pointed me to the following thread at Computing.Net :-) http://www.computing.net/unix/wwwboard/forum/5992.html Many thanks to Joe who initiated the above thread and to Jim who provided the explanation I missed until now. Jim wrote: "With sed the newline character would not be available for elimination with a substitution command without pulling a second line into the buffer with the N command." Tug