make all
./wall
The original version did not have a ‘;’ character in the first line. This caused a number of System V C pre-preprocessors to gripe about a syntax error.
This program is a masterpiece of obfuscation and humor. Larry Wall (the hacker who gave us rn and patch) asks you to compile and consider the warning message generated by the C compiler. Then execute the program and type characters into its standard input. You will see why the compiler documents the program.
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