Lex Murphy is the young hacker who helps restart Jurassic Park’s systems.
In the 1993 film, Lex is the granddaughter of park creator John Hammond and the older sister of Tim Murphy. Dennis Nedry’s sabotage shuts down the park’s security and computer systems, leaving Lex, Tim, Alan Grant, and others trapped among the escaped dinosaurs.
Lex’s computer skills become crucial when the group reaches the visitor center. She uses the Unix-based security interface to access the park’s systems and restore the electronic locks. The scene is remembered for the line about the system being “a UNIX system,” though the film’s interface is a stylized fictional representation.
Lex was played by Ariana Richards. Tim was played by Joseph Mazzello, so the two children are often distinguished by their different roles: Tim is especially fascinated by dinosaurs, while Lex provides the technical expertise needed during the crisis.