One-liner program

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In computer programming, a one-liner program originally was textual input to the command line of an operating system shell that performed some function in just one line of input. In the present day, a one-liner can be

• an expression written in the language of the shell;
• the invocation of an interpreter together with program source for the interpreter to run;
• the invocation of a compiler together with source to compile and instructions for executing the compiled program.

Certain dynamic languages for scripting, such as AWK, sed, and Perl, have traditionally been adept at expressing one-liners. Shell interpreters such as Unix shells or Windows PowerShell allow for the construction of powerful one-liners.

The use of the phrase one-liner has been widened to also include program-source for any language that does something useful in one line.