| This document details the incompatibilites between this version of bash, |
| bash-2.01, and the previous widely-available version, bash-1.14. These |
| were discovered by alpha and beta testers, so they will likely be |
| encountered by a significant number of users. |
| |
| 1. Bash now uses a new quoting syntax, $"...", to do locale-specific |
| string translation. Users who have relied on the (undocumented) |
| behavior of bash-1.14 will have to change their scripts. For |
| instance, if you are doing something like this to get the value of |
| a variable whose name is the value of a second variable: |
| |
| eval var2=$"$var1" |
| |
| you will have to change to a different syntax. |
| |
| This capability is directly supported by bash-2.0: |
| |
| var2=${!var1} |
| |
| This alternate syntax will work portably between bash-1.14 and bash-2.0: |
| |
| eval var2=\$${var1} |
| |
| 2. One of the bugs fixed in the YACC grammar tightens up the rules |
| concerning group commands ( {...} ). The `list' that composes the |
| body of the group command must be terminated by a newline or |
| semicolon. That's because the braces are reserved words, and are |
| recognized as such only when a reserved word is legal. This means |
| that while bash-1.14 accepted shell function definitions like this: |
| |
| foo() { : } |
| |
| bash-2.0 requires this: |
| |
| foo() { :; } |
| |
| This is also an issue for commands like this: |
| |
| mkdir dir || { echo 'could not mkdir' ; exit 1; } |
| |
| The syntax required by bash-2.0 is also accepted by bash-1.14. |
| |
| 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 |
| `bind -P' instead. |
| |
| 4. The `long' invocation options must now be prefixed by `--' instead |
| of `-'. (The old form is still accepted, for the time being.) |
| |
| 5. There was a bug in the version of readline distributed with bash-1.14 |
| that caused it to write badly-formatted key bindings when using |
| `bind -d'. The only key sequences that were affected are C-\ (which |
| should appear as \C-\\ in a key binding) and C-" (which should appear |
| as \C-\"). If these key sequences appear in your inputrc, as, for |
| example, |
| |
| "\C-\": self-insert |
| |
| they will need to be changed to something like the following: |
| |
| "\C-\\": self-insert |
| |
| 6. A number of people complained above having to use ESC to terminate an |
| incremental search, and asked for an alternate mechanism. Bash-2.0 |
| allows ^J to terminate the search without accepting the line. Use |
| ^M to terminate the search and accept the line, as in bash-1.14. |
| |
| 7. Some variables have been removed: MAIL_WARNING, notify, history_control, |
| command_oriented_history, glob_dot_filenames, allow_null_glob_expansion, |
| nolinks, hostname_completion_file, noclobber, no_exit_on_failed_exec, and |
| cdable_vars. Most of them are now implemented with the new `shopt' |
| builtin; others were already implemented by `set'. Here is a list of |
| correspondences: |
| |
| MAIL_WARNING shopt mailwarn |
| notify set -o notify |
| history_control HISTCONTROL |
| command_oriented_history shopt cmdhist |
| glob_dot_filenames shopt dotglob |
| allow_null_glob_expansion shopt nullglob |
| nolinks set -o physical |
| hostname_completion_file HOSTFILE |
| noclobber set -o noclobber |
| no_exit_on_failed_exec shopt execfail |
| cdable_vars shopt cdable_vars |
| |
| 8. `ulimit' now sets both hard and soft limits and reports the soft limit |
| by default (when neither -H nor -S is specified). This is compatible |
| with versions of sh and ksh that implement `ulimit'. The bash-1.14 |
| behavior of, for example, |
| |
| ulimit -c 0 |
| |
| can be obtained with |
| |
| ulimit -S -c 0 |
| |
| It may be useful to define an alias: |
| |
| alias ulimit="ulimit -S" |
| |
| 9. Bash-2.01 uses a new quoting syntax, $'...' to do ANSI-C string |
| translation. Backslash-escaped characters in ... are expanded and |
| replaced as specified by the ANSI C standard. |
| |
| 10. The sourcing of startup files has changed somewhat. This is explained |
| more completely in the INVOCATION section of the manual page. |
| |
| A non-interactive shell not named `sh' and not in posix mode reads |
| and executes commands from the file named by $BASH_ENV. A |
| non-interactive shell started by `su' and not in posix mode will read |
| startup files. No other non-interactive shells read any startup files. |
| |
| An interactive shell started in posix mode reads and executes commands |
| from the file named by $ENV. |