Features Introduced Past 1979
Over the years, the Bourne shell was enhanced at AT&T. The various variants are thus called like the respective AT&T Unix version it was released with (some important variants being Version7, SystemIII, SVR2, SVR3, SVR4). As the shell was never versioned, the only way to identify it was testing its features.
Features of the Bourne shell versions since 1979 include:
- Built-in test command – System III shell (1981)
- # as comment character – System III shell (1981)
- Colon in parameter substitutions "${parameter:=word}" – System III shell (1981)
- Functions and the return builtin – SVR2 shell (1984)
- Built-ins unset, echo, type – SVR2 shell (1984)
- Source code de-ALGOL68-ized – SVR2 shell (1984)
- Modern "$@" – SVR3 shell (1986)
- Built-in getopts – SVR3 shell (1986)
- Cleaned up parameter handling allows recursively callable functions – SVR3 shell (1986)
- 8-bit clean – SVR3 shell (1986)
- Job control – SVR4 shell (1989)
- Multi-byte support – SVR4 shell (1989)
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Famous quotes containing the words features and/or introduced:
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—Henry David Thoreau (1817–1862)
“By this contrivance the machinery of my work is of a species by itself; two contrary motions are introduced into it, and reconciled, which were thought to be at variance with each other. In a word, my work is digressive, and it is progressive too,—and at the same time.”
—Laurence Sterne (1713–1768)