In most command line interface "cli" programs the Option-arrow key combinations allows one to move forwards/backwards a word at a time. But in psql both Option-arrow and Control-Arrow actually insert non printable control characters that corrupt the command. In addition in most CLI programs hitting CTL-A goes to the beginning of the command and CTL-E goes to the end of the command. But in psql those combinations do not have any effect.
Navigating a single character at a time is simply too slow: I can not imagine this were an unsolved problem. What is the configuration needed to get one of those key combinations to skip forward/backward by words not characters?
This is an answer containing the response in the comment by by #Marth. The ~/.inputrc does cause the issue.
# want vi to be the default editor for readline
set editing-mode vi
$if mode=vi
# normal mode
set keymap vi-command
set keymap vi-insert
"\C-n": backward-kill-word
"\C-p": history-search-backward
$endif
I have completely removed the ~/.inputrc now.
Related
In bash there is a setting (usually on by default) that makes it so that any commands that are preceded by a space aren't recorded into the history file.
Is there anything analogous in psql?
So this is possible.
Add \set HISTCONTROL ignorespace to your .psqlrc file.
Then when you precede a command with a space, say setting a password, it won't be added to the history file.
From the manual:
HISTCONTROL
If this variable is set to ignorespace, lines which begin with a space are not entered into the history list. If set to a value of
ignoredups, lines matching the previous history line are not entered.
A value of ignoreboth combines the two options. If unset, or if set to
none (or any other value than those above), all lines read in
interactive mode are saved on the history list.
I am slightly confused by the difference between keys and key-bindings in emacs after reading the first chapter of "Writing GNU Emacs Extensions" (O'Reilly book).
The chapter starts by noting that in some emacs version the keys backspace and DEL, invoke the help menu instead of deleting. In other words, they invoke what is invoked by C-h.
The chapter then goes on to show how to change this behaviour using Lisp code. This is done by binding the keystroke C-h to the delete command.
This is a bit confusing to me. In my mind DEL, Backspace and C-h are three different keystrokes (the first two consisting of a single key).
Why does remapping C-h effect what DEL and Backspace does?
I would have thought to change what backspace does for example, you would remap backspace to another command, not the keystroke C-h.
Unless remapped by a low-level keybord driver, the effect of the Backspace key is to send the character with numeric code 8, which, in certain operating systems, is exactly the same code generated by pressing Control-h. You can verify this fact by simply writing anything on a unix (or linux) shell and then pressing Backspace and Control-h: both of them have the effect of erasing the previous character, since the character with numeric code 8 is interpreted by the operating system as the control character BS, backspace, used either to erase the last character printed or to overprint it (see wikipedia). Analogously, Control-J is equivalent to the RETURN key, etc.
The same Wikipedia page describe DEL as “originally intended to be an ignored character, but now used in some systems to erase a character”.
So, when you assign a command to a keystroke you are actually assigning a command to a character code, and if two or more keys generate the same code, by pressing them you are invoking the same command.
#Renzo answered your question about how these keys are related and how binding one can seem to affect another. Here is some more information about what's going on in this particular case.
See the Emacs manual, node DEL Does Not Delete.
There you will see this, following an explanation of the problem/confusion:
To fix the problem in every Emacs session, put one of the following
lines into your initialization file (*note Init File::). For the first
case above, where BACKSPACE deletes forwards instead of backwards, use
this line to make BACKSPACE act as DEL:
(normal-erase-is-backspace-mode 0)
For the other two cases, use this line:
(normal-erase-is-backspace-mode 1)
Another way to fix the problem for every Emacs session is to
customize the variable normal-erase-is-backspace: the value t
specifies the mode where BS or BACKSPACE is DEL, and nil
specifies the other mode. *Note Easy Customization::.
See also the GNU Emacs FAQ question about Backspace invoking help. There you will see, in addition to information similar to that above, information about how to remap DEL on UNIX - use this:
stty erase '^?'
Wrt C-j and RET (not mentioned in the question, but mentioned in #Renzo's answer): The default behavior of Emacs changed in most programming modes, in Emacs 24.4.
Starting with that release, electric--indent-mode is turned on by default, which means that RET inserts a newline character and indents, whereas C-j just inserts a newline character. Prior to that release, these keys had the opposite behaviors. If you prefer the old behavior then do this, to turn off electric-indent-mode:
(when (fboundp 'electric-indent-mode)
(electric-indent-mode -1)) ; Use classic `C-j' and `RET'.
Context
Have some transcript files from terminal interaction, obtained using traditional Unix command "script".
Those transcripts contain lots of control character (like backspace when editing shell commands), and lots of color code sequences as result of running various commands. Occasionally, even colorful full-terminal (ncurses-based) applications like "emacs -nw" or "aptitude" were run.
At program runtime, TERM environment variable was set as "xterm".
Need 1: read (more or less solved)
I need to read those files again and sometimes copy-paste some small parts.
The trouble is : while one color change here and there is not so much of a problem, their actual density makes the output barely readable. Worse, edited command lines (with cursor jumps and edited words) are completely unreadable.
"Okay" solution
Browse through files using e.g. "less -r". Paging forward in the same terminal setup reproduces the various color and character style.
But many other features come out more or less broken, e.g. search backwards produces jumbled terminal output, often have to pres "Ctrl-L" to clean thing up.
Need 2: editing
My preferred editor is emacs. Some people have had a similar situation when running the shell inside emacs, e.g. Something wrong with Emacs shell.
Here is not the same situation. Examples of differences: here we don't have to run an actual shell, but we need to move cursor freely like in usual editing.
Editing here means easily open such a transcript file in editor and then:
at all times through editing, see character changes (color, attributes) as conveyed by the terminal codes
(optional) some character that are neighbour on the terminal grid but are separated in file by some control characters would have a visual hint about this
ability to insert some text,
delete sections,
use all editor features like search/replace etc.
copy & paste to & from file (including to external programs, which would receive just plain text)
in my wildest dreams, some kind of "flatten" action, like select a sequence with a heavily edited command line and replace it with a simple series of characters as if it was typed in one run. "Visual hints" mentioned above would disappear.
Type Alt-: to evaluate something in the minibuffer. Evaluate (ansi-color-apply-on-region (point-min) (point-max)) and it will convert ansi color codes to be font colors.
In GNU screen, I want to change the default command binding to Alt-s (by tweaking .screenrc) instead of the default C-a, the reason is I use emacs hence GNU screen binds the C-a key, sending "C-a" to the emacs becomes tedious (as #Nils said, to send "C-a" I should type "C-a a"), as well as "C-a" in bash shell, and I could change the escape to C- but some of them are already mapped in emacs and other combinations are not as easy as ALT-s . If anyone has already done a ALT key mapping, please do let me know.
It is possible to work around :escape command limitations using registers and :bindkey command. Just put this in .screenrc:
# reset escape key to the default
escape ^Aa
# auxiliary register
register S ^A
# Alt + x produces ^A and acts as an escape key
bindkey "^[x" process S
## Alt + space produces ^A and acts as an escape key
# bindkey "^[ " process S
See http://adb.cba.pl/gnu-screen-tips-page-my.html#howto-alt-key-as-escape
From my reading of man screen it seems like the only meta character that screen can use for the command binding is CTRL:
escape xy
Set the command character to x and the character generating a literal
command character (by triggering the "meta" command) to y (similar to
the -e option). Each argument is either a single character, a two-character
sequence of the form "^x" (meaning "C-x"), a backslash followed by an octal
number (specifying the ASCII code of the character), or a backslash followed
by a second character, such as "\^" or "\\". The default is "^Aa".
If there is some mapping that you don't use in emacs, even if it's inconvenient, like C-|, then you could use your terminal input manager to remap ALT-X to that, letting you use the ALT binding instead. That would be a little hackish though.
I'm an Emacs and screen user as well. Although I rarely use Emacs in a terminal -- and as such in a screen session -- I didn't want to give up C-a for the shell either (which uses Emacs key bindings). My solution was to use C-j as the prefix key for screen, which I was willing to sacrifice. In Emacs programming modes it is bound to (newline-and-indent) which I bound to RET as well, so I really don't miss it.
By the way: I know this is an advise rather than an answer, but I felt this would be valuable enough to post nevertheless.
To make Alt+X the default prefix for commands and free C-a, add the following lines to .screenrc:
escape ^||
bindkey "^[x" command
As a side effect C-| will be command prefix too. If you need this keys to be free too, then fix "escape ^||" accordingly.
Screen doesn't have any shorthand syntax for alt bindings, but you can give it the octal code directly. For instance on my machine, Alt-x has the hex code F8, or 370 octal, so putting
escape \370x
in my screenrc changed the escape code to alt-X
Tested and works with screen 4.00.03 on Linux.
You may have to change the escape, since I think this may depend on things like your language and codeset, etc: how I found out what my escape code was was to type
$ echo -n ^QM-x | perl -ne 'printf "%lo\n", ord($_)'
^Q is the quoted-insert command for readline (it inserts what you type directly without trying to interpret it) and M-x was a literal Alt-X.
Fellow emacs user here.
The best solution I've found is a ~/.screenrc file with the following:
# C-a :source .screenrc
escape ^gg
Live updated here: https://gist.github.com/1058111
See also: http://ubuntuforums.org/showthread.php?t=498675
Something I have had for years in my .screenrc:
escape ^Zz
which is now hardwired in muscle memory for me.
Somehow I ended up having to share a screen with someone else's config, and now I keep stopping processes all the time (bash ^Z)... Not funny...
I'm using psql 8.2.3 on FreeBSD. Every time I press Insert, Home, Delete, End, Page Up or Page Down, a tilde (~) character is inserted instead of performing the expected function of the key. Why does this happen and how can I fix it?
As mentioned in Endlessdeath's answer, this turned out to be a key mapping problem with the operating system (FreeBSD), not psql. You can make these keys work as expected by creating or adding to a configuration file for inputrc.
You can create a file named .inputrc in your home directory with the following:
set meta-flag on
set input-meta on
set convert-meta off
set output-meta on
"\e[1~": beginning-of-line
"\e[4~": end-of-line
"\e[5~": beginning-of-history
"\e[6~": end-of-history
"\e[3~": delete-char
"\e[2~": quoted-insert
"\e[5C": forward-word
"\e[5D": backward-word
Alternatively, you can create a global file for all users. A common practice for this is to create or add to the file at /usr/local/etc/inputrc the same lines as above and then export the variable in /etc/profile:
export INPUTRC=/usr/local/etc/inputrc
Ensure that /etc/profile is sourced by your shell (most do by default) and you're good to go. Note that the file won't be sourced until you log out and in again.
Here are some other resources for this problem:
http://bsdpants.blogspot.com/2007/08/make-home-and-end-keys-work.html
http://www.cyberciti.biz/tips/freebsd-how-to-customized-home-del-insert-keys-for-bash-shell.html
http://www.ibb.net/~anne/keyboard.html
That shouldn't be a psql problem - it's os specific.
A quick search on google could help.