| Line 4355... |
Line 4355... |
| 4355 |
Bash extensions also need to be avoided in shell scripts, including
|
4355 |
Bash extensions also need to be avoided in shell scripts, including
|
| 4356 |
expressions in Makefiles (which are passed to the shell for processing).
|
4356 |
expressions in Makefiles (which are passed to the shell for processing).
|
| 4357 |
Some @R{} platforms use strict@footnote{For example, @command{test}
|
4357 |
Some @R{} platforms use strict@footnote{For example, @command{test}
|
| 4358 |
options @option{-a} and @option{-e} are not portable, and not supported
|
4358 |
options @option{-a} and @option{-e} are not portable, and not supported
|
| 4359 |
in the AT&T Bourne shell used on Solaris 10/11, even though they are in
|
4359 |
in the AT&T Bourne shell used on Solaris 10/11, even though they are in
|
| 4360 |
the 2008 POSIX standard. Nor does Solaris support @samp{$(@var{cmd})}.}
|
4360 |
the POSIX standard. Nor does Solaris support @samp{$(@var{cmd})}.}
|
| 4361 |
Bourne shells: the @R{} toolset on Windows and some Unix-alike OSes use
|
4361 |
Bourne shells: the @R{} toolset on Windows and some Unix-alike OSes use
|
| 4362 |
@command{ash} (@uref{https://en.wikipedia.org/@/wiki/@/Almquist_shell}),
|
4362 |
@command{ash} (@uref{https://en.wikipedia.org/@/wiki/@/Almquist_shell}),
|
| 4363 |
a rather minimal shell with few builtins. Beware of assuming that all
|
4363 |
a rather minimal shell with few builtins. Beware of assuming that all
|
| 4364 |
the POSIX command-line utilities are available, especially on Windows
|
4364 |
the POSIX command-line utilities are available, especially on Windows
|
| 4365 |
where only a minimal set is provided for use with @R{}.
|
4365 |
where only a minimal set is provided for use with @R{}.
|
| Line 4377... |
Line 4377... |
| 4377 |
export FOO=value
|
4377 |
export FOO=value
|
| 4378 |
@end example
|
4378 |
@end example
|
| 4379 |
@noindent
|
4379 |
@noindent
|
| 4380 |
which is bash-specific (first set the variable then export it by name).
|
4380 |
which is bash-specific (first set the variable then export it by name).
|
| 4381 |
|
4381 |
|
| 4382 |
@code{test -e} (or @code{[ -e ]} in shell scripts is not portable:
|
4382 |
Using @code{test -e} (or @code{[ -e ]}) in shell scripts is not
|
| 4383 |
@code{-f} is normally what is intended.
|
4383 |
portable: @code{-f} is normally what is intended. Flags @option{-a} and
|
| - |
|
4384 |
@option{-o} are nowadays declared obsolescent by POSIX and should not be
|
| - |
|
4385 |
used.
|
| 4384 |
|
4386 |
|
| - |
|
4387 |
The @option{-o} flag for @command{set} in shell scripts is optional in
|
| - |
|
4388 |
POSIX and not supported on all the platforms @R{} is used on.
|
| - |
|
4389 |
|
| 4385 |
On macOS Catalina and later, which shell @file{/bin/sh} invokes is user-
|
4390 |
On macOS Catalina which shell @file{/bin/sh} invokes is user- and
|
| 4386 |
and platform-dependent: it might be @command{bash} version 3.2,
|
4391 |
platform-dependent: it might be @command{bash} version 3.2,
|
| 4387 |
@command{dash} or @command{zsh} (for new accounts it is @command{zsh},
|
4392 |
@command{dash} or @command{zsh} (for new accounts it is @command{zsh},
|
| 4388 |
for accounts ported from earlier version it is usually @command{bash}).
|
4393 |
for accounts ported from earlier version it is usually @command{bash}).
|
| 4389 |
|
4394 |
|
| 4390 |
@item
|
4395 |
@item
|
| 4391 |
Make use of the abilities of your compilers to check the
|
4396 |
Make use of the abilities of your compilers to check the
|
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