-
6.11 Bash POSIX Mode
====================
14. Non-interactive shells exit if a syntax error in an arithmetic
expansion results in an invalid expression.
- 15. Non-interactive shells exit if there is a syntax error in a script
+ 15. Non-interactive shells exit on word expansion errors.
+
+ 16. Non-interactive shells exit if there is a syntax error in a script
read with the '.' or 'source' builtins, or in a string processed by
the 'eval' builtin.
- 16. Redirection operators do not perform filename expansion on the
+ 17. Redirection operators do not perform filename expansion on the
word in the redirection unless the shell is interactive.
- 17. Redirection operators do not perform word splitting on the word in
+ 18. Redirection operators do not perform word splitting on the word in
the redirection.
- 18. Function names must be valid shell 'name's. That is, they may not
+ 19. Function names must be valid shell 'name's. That is, they may not
contain characters other than letters, digits, and underscores, and
may not start with a digit. Declaring a function with an invalid
name causes a fatal syntax error in non-interactive shells.
- 19. Function names may not be the same as one of the POSIX special
+ 20. Function names may not be the same as one of the POSIX special
builtins.
- 20. POSIX special builtins are found before shell functions during
+ 21. POSIX special builtins are found before shell functions during
command lookup.
- 21. Literal tildes that appear as the first character in elements of
+ 22. Literal tildes that appear as the first character in elements of
the 'PATH' variable are not expanded as described above under *note
Tilde Expansion::.
- 22. The 'time' reserved word may be used by itself as a command. When
+ 23. The 'time' reserved word may be used by itself as a command. When
used in this way, it displays timing statistics for the shell and
its completed children. The 'TIMEFORMAT' variable controls the
format of the timing information.
- 23. When parsing and expanding a ${...} expansion that appears within
+ 24. When parsing and expanding a ${...} expansion that appears within
double quotes, single quotes are no longer special and cannot be
used to quote a closing brace or other special character, unless
the operator is one of those defined to perform pattern removal.
In this case, they do not have to appear as matched pairs.
- 24. The parser does not recognize 'time' as a reserved word if the
+ 25. The parser does not recognize 'time' as a reserved word if the
next token begins with a '-'.
- 25. If a POSIX special builtin returns an error status, a
+ 26. If a POSIX special builtin returns an error status, a
non-interactive shell exits. The fatal errors are those listed in
the POSIX standard, and include things like passing incorrect
options, redirection errors, variable assignment errors for
assignments preceding the command name, and so on.
- 26. A non-interactive shell exits with an error status if a variable
+ 27. A non-interactive shell exits with an error status if a variable
assignment error occurs when no command name follows the assignment
statements. A variable assignment error occurs, for example, when
trying to assign a value to a readonly variable.
- 27. A non-interactive shell exits with an error status if a variable
+ 28. A non-interactive shell exits with an error status if a variable
assignment error occurs in an assignment statement preceding a
special builtin, but not with any other simple command.
- 28. A non-interactive shell exits with an error status if the
+ 29. A non-interactive shell exits with an error status if the
iteration variable in a 'for' statement or the selection variable
in a 'select' statement is a readonly variable.
- 29. Process substitution is not available.
+ 30. Process substitution is not available.
- 30. While variable indirection is available, it may not be applied to
+ 31. While variable indirection is available, it may not be applied to
the '#' and '?' special parameters.
- 31. Assignment statements preceding POSIX special builtins persist in
+ 32. Assignment statements preceding POSIX special builtins persist in
the shell environment after the builtin completes.
- 32. Assignment statements preceding shell function calls persist in
+ 33. Assignment statements preceding shell function calls persist in
the shell environment after the function returns, as if a POSIX
special builtin command had been executed.
- 33. The 'export' and 'readonly' builtin commands display their output
+ 34. The 'export' and 'readonly' builtin commands display their output
in the format required by POSIX.
- 34. The 'trap' builtin displays signal names without the leading
+ 35. The 'trap' builtin displays signal names without the leading
'SIG'.
- 35. The 'trap' builtin doesn't check the first argument for a possible
+ 36. The 'trap' builtin doesn't check the first argument for a possible
signal specification and revert the signal handling to the original
disposition if it is, unless that argument consists solely of
digits and is a valid signal number. If users want to reset the
handler for a given signal to the original disposition, they should
use '-' as the first argument.
- 36. The '.' and 'source' builtins do not search the current directory
+ 37. The '.' and 'source' builtins do not search the current directory
for the filename argument if it is not found by searching 'PATH'.
- 37. Subshells spawned to execute command substitutions inherit the
+ 38. Subshells spawned to execute command substitutions inherit the
value of the '-e' option from the parent shell. When not in POSIX
mode, Bash clears the '-e' option in such subshells.
- 38. Alias expansion is always enabled, even in non-interactive shells.
+ 39. Alias expansion is always enabled, even in non-interactive shells.
- 39. When the 'alias' builtin displays alias definitions, it does not
+ 40. When the 'alias' builtin displays alias definitions, it does not
display them with a leading 'alias ' unless the '-p' option is
supplied.
- 40. When the 'set' builtin is invoked without options, it does not
+ 41. When the 'set' builtin is invoked without options, it does not
display shell function names and definitions.
- 41. When the 'set' builtin is invoked without options, it displays
+ 42. When the 'set' builtin is invoked without options, it displays
variable values without quotes, unless they contain shell
metacharacters, even if the result contains nonprinting characters.
- 42. When the 'cd' builtin is invoked in LOGICAL mode, and the pathname
+ 43. When the 'cd' builtin is invoked in LOGICAL mode, and the pathname
constructed from '$PWD' and the directory name supplied as an
argument does not refer to an existing directory, 'cd' will fail
instead of falling back to PHYSICAL mode.
- 43. The 'pwd' builtin verifies that the value it prints is the same as
+ 44. The 'pwd' builtin verifies that the value it prints is the same as
the current directory, even if it is not asked to check the file
system with the '-P' option.
- 44. When listing the history, the 'fc' builtin does not include an
+ 45. When listing the history, the 'fc' builtin does not include an
indication of whether or not a history entry has been modified.
- 45. The default editor used by 'fc' is 'ed'.
+ 46. The default editor used by 'fc' is 'ed'.
- 46. The 'type' and 'command' builtins will not report a non-executable
+ 47. The 'type' and 'command' builtins will not report a non-executable
file as having been found, though the shell will attempt to execute
such a file if it is the only so-named file found in '$PATH'.
- 47. The 'vi' editing mode will invoke the 'vi' editor directly when
+ 48. The 'vi' editing mode will invoke the 'vi' editor directly when
the 'v' command is run, instead of checking '$VISUAL' and
'$EDITOR'.
- 48. When the 'xpg_echo' option is enabled, Bash does not attempt to
+ 49. When the 'xpg_echo' option is enabled, Bash does not attempt to
interpret any arguments to 'echo' as options. Each argument is
displayed, after escape characters are converted.
- 49. The 'ulimit' builtin uses a block size of 512 bytes for the '-c'
+ 50. The 'ulimit' builtin uses a block size of 512 bytes for the '-c'
and '-f' options.
- 50. The arrival of 'SIGCHLD' when a trap is set on 'SIGCHLD' does not
+ 51. The arrival of 'SIGCHLD' when a trap is set on 'SIGCHLD' does not
interrupt the 'wait' builtin and cause it to return immediately.
The trap command is run once for each child that exits.
- 51. The 'read' builtin may be interrupted by a signal for which a trap
+ 52. The 'read' builtin may be interrupted by a signal for which a trap
has been set. If Bash receives a trapped signal while executing
'read', the trap handler executes and 'read' returns an exit status
greater than 128.
projects / thirdparty / bash.git / blobdiff