Bourne Shell: Difference between revisions
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'''Portable Shell Syntax''' is the scripting language syntax used by the System V Bourne shell. This syntax is compatible with the heirloom shell and is the syntax documented in most Unix books.▼
▲'''Portable Shell Syntax''' is the scripting language syntax used by the [[wp:UNIX System V|System V]] Bourne shell. This syntax is compatible with the heirloom shell and is the syntax documented in most Unix books. Examples marked "Works with: Bourne Shell" should work in any of the Bourne-compatible shells.
▲{{implementation|UNIX Shell}}The [[wp:bourne shell|'''Bourne Shell''']] is a UNIX shell upon which many shells are based; notably ksh and bash. (The other major tree of UNIX shells descend from csh)
A Bourne Shell script begins with a [[
<syntaxhighlight lang="sh">
</syntaxhighlight>
In 2009, ''[[wp:Computerworld|Computerworld]]
== Bugs ==
Bourne Shell and Heirloom Shell have problems with here documents. Here is one such problem. A substitution, inside a here document, inside backquotes, inside double quotes, does insert too many backslashes.
<syntaxhighlight lang="sh">f() {
cat <<!
here $1
!
}
expr "`f string`"
# Output from Bourne Shell: here \s\t\r\i\n\g
# Correct output: here string</syntaxhighlight>
The workaround is to move the backquotes to an assignment.
<syntaxhighlight lang="sh">f() {
cat <<!
here $1
!
}
var=`f string`
expr "$var"
# Output: here string</syntaxhighlight>
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