pg is a terminal pager program on Unix and Unix-like systems for viewing text files.
pg uses an interface similar to vi, but commands are different.
[1] As of 2018, pg has been removed[2] from the POSIX specification, but is still included in util-linux.
pg is the name of the historical utility on BSD UNIX systems.
It was written to address the limit of the historical more command not being able to traverse the input backward.