This document details the incompatibilites between this version of bash,
-bash-2.04, and the previous widely-available version, bash-1.14 (which
-is still the `standard' version for many Linux distributions). These
-were discovered by users of bash-2.x, so this list is not comprehensive.
-
-1. Bash now uses a new quoting syntax, $"...", to do locale-specific
+bash-3.1, and a previous widely-available version, bash-1.14 (which
+is still the `standard' version for a few Linux distributions). These
+were discovered by users of bash-2.x and 3.x, so this list is not
+comprehensive. Some of these incompatibilities occur between the current
+version and versions 2.0 and above. (The differences between bash-1.14
+and bash-2.0 were significant.)
+
+1. Bash uses a new quoting syntax, $"...", to do locale-specific
string translation. Users who have relied on the (undocumented)
behavior of bash-1.14 will have to change their scripts. For
instance, if you are doing something like this to get the value of
3. The options to `bind' have changed to make them more consistent with
the rest of the bash builtins. If you are using `bind -d' to list
- the readline keybindings in a form that can be re-read, use `bind -p'
- instead. If you were using `bind -v' to list the keybindings, use
+ the readline key bindings in a form that can be re-read, use `bind -p'
+ instead. If you were using `bind -v' to list the key bindings, use
`bind -P' instead.
4. The `long' invocation options must now be prefixed by `--' instead
"\C-\\": self-insert
-6. A number of people complained above having to use ESC to terminate an
+6. A number of people complained about having to use ESC to terminate an
incremental search, and asked for an alternate mechanism. Bash-2.03
uses the value of the settable readline variable `isearch-terminators'
to decide which characters should terminate an incremental search. If
that declares them:
alias -x='chmod a-x' --> alias -- -x='chmod a-x'
+
+13. The behavior of range specificiers within bracket matching expressions
+ in the pattern matcher (e.g., [A-Z]) depends on the current locale,
+ specifically the value of the LC_COLLATE environment variable. Setting
+ this variable to C or POSIX will result in the traditional ASCII behavior
+ for range comparisons. If the locale is set to something else, e.g.,
+ en_US (specified by the LANG or LC_ALL variables), collation order is
+ locale-dependent. For example, the en_US locale sorts the upper and
+ lower case letters like this:
+
+ AaBb...Zz
+
+ so a range specification like [A-Z] will match every letter except `z'.
+ Other locales collate like
+
+ aAbBcC...zZ
+
+ which means that [A-Z] matches every letter except `a'.
+
+ The portable way to specify upper case letters is [:upper:] instead of
+ A-Z; lower case may be specified as [:lower:] instead of a-z.
+
+ Look at the manual pages for setlocale(3), strcoll(3), and, if it is
+ present, locale(1).
+
+ You can find your current locale information by running locale(1):
+
+ caleb.ins.cwru.edu(2)$ locale
+ LANG=en_US
+ LC_CTYPE="en_US"
+ LC_NUMERIC="en_US"
+ LC_TIME="en_US"
+ LC_COLLATE="en_US"
+ LC_MONETARY="en_US"
+ LC_MESSAGES="en_US"
+ LC_ALL=en_US
+
+ My advice is to put
+
+ export LC_COLLATE=C
+
+ into /etc/profile and inspect any shell scripts run from cron for
+ constructs like [A-Z]. This will prevent things like
+
+ rm [A-Z]*
+
+ from removing every file in the current directory except those beginning
+ with `z' and still allow individual users to change the collation order.
+ Users may put the above command into their own profiles as well, of course.
+
+14. Bash versions up to 1.14.7 included an undocumented `-l' operator to
+ the `test/[' builtin. It was a unary operator that expanded to the
+ length of its string argument. This let you do things like
+
+ test -l $variable -lt 20
+
+ for example.
+
+ This was included for backwards compatibility with old versions of the
+ Bourne shell, which did not provide an easy way to obtain the length of
+ the value of a shell variable.
+
+ This operator is not part of the POSIX standard, because one can (and
+ should) use ${#variable} to get the length of a variable's value.
+ Bash-2.x does not support it.
+
+15. Bash no longer auto-exports the HOME, PATH, SHELL, TERM, HOSTNAME,
+ HOSTTYPE, MACHTYPE, or OSTYPE variables.
+
+16. Bash no longer initializes the FUNCNAME, GROUPS, or DIRSTACK variables
+ to have special behavior if they appear in the initial environment.
+
+17. Bash no longer removes the export attribute from the SSH_CLIENT or
+ SSH2_CLIENT variables, and no longer attempts to discover whether or
+ not it has been invoked by sshd in order to run the startup files.
+
+18. Bash no longer requires that the body of a function be a group command;
+ any compound command is accepted.
+
+19. As of bash-3.0, the pattern substitution operators no longer perform
+ quote removal on the pattern before attempting the match. This is the
+ way the pattern removal functions behave, and is more consistent.
+
+20. After bash-3.0 was released, I reimplemented tilde expansion, incorporating
+ it into the mainline word expansion code. This fixes the bug that caused
+ the results of tilde expansion to be re-expanded. There is one
+ incompatibility: a ${paramOPword} expansion within double quotes will not
+ perform tilde expansion on WORD. This is consistent with the other
+ expansions, and what POSIX specifies.
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