COMPAT

   1 This document details the incompatibilites between this version of bash,
   2 bash-2.01, and the previous widely-available version, bash-1.14.  These
   3 were discovered by alpha and beta testers, so they will likely be
   4 encountered by a significant number of users.
   5
   6 1.  Bash now uses a new quoting syntax, $"...", to do locale-specific
   7     string translation.  Users who have relied on the (undocumented)
   8     behavior of bash-1.14 will have to change their scripts.  For
   9     instance, if you are doing something like this to get the value of
  10     a variable whose name is the value of a second variable:
  11
  12         eval var2=$"$var1"
  13
  14     you will have to change to a different syntax.
  15
  16     This capability is directly supported by bash-2.0:
  17
  18         var2=${!var1}
  19
  20     This alternate syntax will work portably between bash-1.14 and bash-2.0:
  21
  22         eval var2=\$${var1}
  23
  24 2.  One of the bugs fixed in the YACC grammar tightens up the rules
  25     concerning group commands ( {...} ).  The `list' that composes the
  26     body of the group command must be terminated by a newline or
  27     semicolon.  That's because the braces are reserved words, and are
  28     recognized as such only when a reserved word is legal.  This means
  29     that while bash-1.14 accepted shell function definitions like this:
  30
  31         foo() { : }
  32
  33     bash-2.0 requires this:
  34
  35         foo() { :; }
  36
  37     This is also an issue for commands like this:
  38
  39         mkdir dir || { echo 'could not mkdir' ; exit 1; }
  40
  41     The syntax required by bash-2.0 is also accepted by bash-1.14.
  42
  43 3.  The options to `bind' have changed to make them more consistent with
  44     the rest of the bash builtins.  If you are using `bind -d' to list
  45     the readline keybindings in a form that can be re-read, use `bind -p'
  46     instead.  If you were using `bind -v' to list the keybindings, use
  47     `bind -P' instead.
  48
  49 4.  The `long' invocation options must now be prefixed by `--' instead
  50     of `-'.  (The old form is still accepted, for the time being.)
  51
  52 5.  There was a bug in the version of readline distributed with bash-1.14
  53     that caused it to write badly-formatted key bindings when using
  54     `bind -d'.  The only key sequences that were affected are C-\ (which
  55     should appear as \C-\\ in a key binding) and C-" (which should appear
  56     as \C-\").  If these key sequences appear in your inputrc, as, for
  57     example,
  58
  59         "\C-\": self-insert
  60
  61     they will need to be changed to something like the following:
  62
  63         "\C-\\": self-insert
  64
  65 6.  A number of people complained above having to use ESC to terminate an
  66     incremental search, and asked for an alternate mechanism.  Bash-2.0
  67     allows ^J to terminate the search without accepting the line.  Use
  68     ^M to terminate the search and accept the line, as in bash-1.14.
  69
  70 7.  Some variables have been removed:  MAIL_WARNING, notify, history_control,
  71     command_oriented_history, glob_dot_filenames, allow_null_glob_expansion,
  72     nolinks, hostname_completion_file, noclobber, no_exit_on_failed_exec, and
  73     cdable_vars.  Most of them are now implemented with the new `shopt'
  74     builtin; others were already implemented by `set'.  Here is a list of
  75     correspondences:
  76
  77         MAIL_WARNING                    shopt mailwarn
  78         notify                          set -o notify
  79         history_control                 HISTCONTROL
  80         command_oriented_history        shopt cmdhist
  81         glob_dot_filenames              shopt dotglob
  82         allow_null_glob_expansion       shopt nullglob
  83         nolinks                         set -o physical
  84         hostname_completion_file        HOSTFILE
  85         noclobber                       set -o noclobber
  86         no_exit_on_failed_exec          shopt execfail
  87         cdable_vars                     shopt cdable_vars
  88
  89 8. `ulimit' now sets both hard and soft limits and reports the soft limit
  90     by default (when neither -H nor -S is specified).  This is compatible
  91     with versions of sh and ksh that implement `ulimit'.  The bash-1.14
  92     behavior of, for example,
  93
  94                 ulimit -c 0
  95
  96     can be obtained with
  97
  98                 ulimit -S -c 0
  99
 100     It may be useful to define an alias:
 101
 102                 alias ulimit="ulimit -S"
 103