SED Spaces (Buffers)

Within sed , there are a number of spaces (or buffers) on which sed commands operate . Each input line is first copied to the pattern space. The pattern space is the temporary holding space on which sed commands are performed. Once the provided sed scripts have all been performed on the pattern space, the line is copied to the output. Also available in sed is the hold space. Within sed , we can copy the contents of the pattern space to the hold space and retrieve them at some later time. The hold space is just a temporary buffer, but it can be useful to remember certain lines.