bash: messed up display for long lines

Question

I am using the GNU bash, version 4.4.0(1) on Ubuntu 16.04.

When I enter long lines in my bash, its display is messed up.

For example, assuming I am in ~/test/test/test/test/test/test/test and I enter echo "The quick brown fox jumps over the lazy doggo" it looks like this: This is halfway okay, even though I would prefer a wrapped display and I could do without the doubling of the line.

The problem is when I now fix the sentence by pressing backspace three times plus double quotes once, the display looks like this:

The o" at the end is a display error, as confirmed by pressing enter:

You can see that the desired sentence with dog instead of doggo is printed. It is printed in green though, for whatever reason.

All of this becomes even worse when I now enlarge and shrink the terminal window a few times. The content of the terminal then gets randomly copied and concatenated throughout the terminal: (The long black boxes are random concatenations of the contents of my prompt.)

I figure all of this could be related to the ~/.bashrc, even though I just did cp /etc/skel/.bashrc ~/. Anyway, here it is:

# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

# don't put duplicate lines or lines starting with space in the history.
# See bash(1) for more options
HISTCONTROL=ignoreboth

# append to the history file, don't overwrite it
shopt -s histappend

# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
HISTSIZE=1000
HISTFILESIZE=2000

# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize

# If set, the pattern "**" used in a pathname expansion context will
# match all files and zero or more directories and subdirectories.
#shopt -s globstar

# make less more friendly for non-text input files, see lesspipe(1)
[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"

# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)
fi

# set a fancy prompt (non-color, unless we know we "want" color)
case "$TERM" in
    xterm-color|*-256color) color_prompt=yes;;
esac

# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt
#force_color_prompt=yes

if [ -n "$force_color_prompt" ]; then
    if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
    # We have color support; assume it's compliant with Ecma-48
    # (ISO/IEC-6429). (Lack of such support is extremely rare, and such
    # a case would tend to support setf rather than setaf.)
    color_prompt=yes
    else
    color_prompt=
    fi
fi

if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi
unset color_prompt force_color_prompt

# If this is an xterm set the title to user@host:dir
case "$TERM" in
xterm*|rxvt*)
    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
    ;;
*)
    ;;
esac

# enable color support of ls and also add handy aliases
if [ -x /usr/bin/dircolors ]; then
    test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"
    alias ls='ls --color=auto'
    #alias dir='dir --color=auto'
    #alias vdir='vdir --color=auto'

    alias grep='grep --color=auto'
    alias fgrep='fgrep --color=auto'
    alias egrep='egrep --color=auto'
fi

# colored GCC warnings and errors
#export GCC_COLORS='error=01;31:warning=01;35:note=01;36:caret=01;32:locus=01:quote=01'

# some more ls aliases
alias ll='ls -alF'
alias la='ls -A'
alias l='ls -CF'

# Add an "alert" alias for long running commands.  Use like so:
#   sleep 10; alert
alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'

# Alias definitions.
# You may want to put all your additions into a separate file like
# ~/.bash_aliases, instead of adding them here directly.
# See /usr/share/doc/bash-doc/examples in the bash-doc package.

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases
fi

# enable programmable completion features (you don't need to enable
# this, if it's already enabled in /etc/bash.bashrc and /etc/profile
# sources /etc/bash.bashrc).
if ! shopt -oq posix; then
  if [ -f /usr/share/bash-completion/bash_completion ]; then
    . /usr/share/bash-completion/bash_completion
  elif [ -f /etc/bash_completion ]; then
    . /etc/bash_completion
  fi
fi

Upon removing ~/.bashrc, I get the following: (I am using the command echo "This is a really long sentence, even long than a sentence containing all letters of the alphabet" to make up for the shorter prompt)

First, everything is fine:

Upon deleting a few words, I get some leftovers at the end of the line:

Furthermore, if I keep pressing backspace, I can even delete parts of the prompt:

After pressing enter (and fixing the end of the command to [...], ev"), and upon resizing, I get the usual mess:

Just for testing and to confirm, what happens when you rename ~/.bashrc to ~/.BACKUPbashrc, log out and login again and do the same echo? — Tigger, Aug 29 '17 at 08:39
@Tigger Strange behavior still happens, but not as strange. See edit — Bananach, Aug 29 '17 at 08:47
What is the result of echo "$TERM"? One possibility is that it may be set incorrectly. — Score_Under, Aug 29 '17 at 10:09
echo $TERM gives xterm-256color, and I am using GNOME Terminal — Bananach, Aug 29 '17 at 10:16
Maybe run PS4=' ${BASH_SOURCE}:${LINENO}: ' bash -lx and see where PS1 is being set — muru, Aug 29 '17 at 10:24
@muru: The output of that command is almost a thousand lines long. I don't know what to do with it — Bananach, Aug 29 '17 at 10:34

Olivier Dulac · Answer 1 · 2017-08-29T16:00:02.710

6

Your prompt contains colors (and maybe other non-printables).

In bash, you can surround the parts with \[ and \] to tell bash to ignore those parts to calculate the length of the prompt.

Ex:

PS1="\e[33mthis is green\e[0m this is normal"
# should be done as:
PS1="\[\e[33m\]this is green\[\e[0m\] this is normal"

The 2nd one has \[ and \] around each part that, while changing the color, doesn't add any visible character in the display, thus should not be counted when calculating the placement of characters on the prompt.

If you modified PS1, make sure you didn't put within \[ and \] visible characters. If you did, get them outside of those.

Another thing : You may want to do shopt -q -s checkwinsize to make sure the terminal size is updated when it is resized.

And you seem to be using a setting that shows only the end of the currently entered command line (similar as what ksh does... are you sure you use bash?) : I'll look into what option can change this, but I don't know it yet.

edit

In chat we also discussed:

set -o emacs  #he was in vi mode
set -o posix  #he was in posix=no mode

but in the end it seems what worked was get rid of ~/.inputrc (which he did, it may have contained something wrong but I don't know what was in it, nor did I asked to delete it ^^ just renaming it (or fixing its content) would have helped...)

edited Aug 29 '17 at 16:00

answered Aug 29 '17 at 14:42

Olivier Dulac

6,285

I am sorry, I tried around inserting \[ and \] but I couldn't get it to anything that works. Could you give me the correct strings I should use? – Bananach Aug 29 '17 at 14:53
My ~/.bashrc is exactly as in the post, it's a bit hidden after the first four figures – Bananach Aug 29 '17 at 14:56
In a nutshell: inset \[ JUST before a "non-displayed" part, and \] JUST after the end of that non-printable part (ie, a part that will not add 1 (or more) character to the prompt string, but instead does other things (change colors, set the title string, etc). Do that for every "non-displayed" part in your PS1 string. – Olivier Dulac Aug 29 '17 at 14:56
I don't know what non displayed parts are. To me every line in ~/.bashrc that contains PS1=[...] looks like just random characters – Bananach Aug 29 '17 at 14:58
Let us continue this discussion in chat. – Bananach Aug 29 '17 at 15:03
I'm still available at the chat, in case you only read this later though: The output is declare -- PS1="\\[\\e]0;\\]\\[\\u@\\h: \\w\\a\\]\${debian_chroot:+(\$debian_chroot)}\\[\\033[01;32m\\u@\\h\\033[00m\\]:\\[\\033[01;34m\\w\\033[00m\\]\\\$ " – Bananach Aug 29 '17 at 15:05
@Bananach: you can play aroudn with : http://ezprompt.net/ to get a feel of the prompt content. And read : man bash and look for PROMPTING (use: /PROMPTING to search the first occurence of that word, then 'n' to get to the next one(s), until you see one that shows all the different values you can use in the PS1 line, \u , \$ , etc) – Olivier Dulac Aug 29 '17 at 15:05
Didn't work. Anyway. I used ezprompt, which is really cool, and used the simple PS1="\u:\w\\$ ". Now the problem is exactly as in the second set of figures in my post (created using no bashrc at all). For example, parts of the prompt are deleted upon pressing backspace too often – Bananach Aug 29 '17 at 15:13
if youre curious, see my answer for what was wrong with '~/.inputrc' and some observations on the PS1 string – Bananach Aug 29 '17 at 16:49

score 3 · Answer 2 · answered Aug 29 '17 at 16:41

I solved this, with help of @OlivierDulac, by making changes to ~/.bashrc and to ~/.inputrc.

In ~/.bashrc I now use:

PS1='\e[01;32m\u:\e[01;34m\w\e[0m\$ '

Note that I replaced \033 by \e to create colors. Doing this alone to the original PS1 didn't fix it, so there is something else wrong with it, but I was too tired to track it down. I believe it is the fact that I (contrary to a lot of recommendations, and contrary to the ezprompt.net, which I used to create the PS1) DO NOT use \[ and \] to enclose non-printed characters. Indeed, if I do use those everything gets messed up again.

In ~/.inputrc, I previously had

#These lines make the vi mode visible by switching from a block cursor to a line cursor.
set show-mode-in-prompt on
[...]
set vi-cmd-mode-string \1\e[1 q\2
set vi-ins-mode-string \1\e[5 q\2

I simply remove the \1 and \2, i.e. I now have

set editing-mode vi
[...]
set show-mode-in-prompt on
set vi-cmd-mode-string \e[1 q
set vi-ins-mode-string \e[5 q

Again, this is contrary to what I was recommended elsewhere. Maybe it is because I am using a relatively new bash? (set show-mode-in-prompt on only works for bash4.4 afaik)

Martie · Answer 3 · 2017-08-29T10:16:50.640

0

Is your terminal setting (terminal type) correct? On my ubuntu linux host my terminal type is 'ansi'. (you can get this by issuing command: echo $TERM ). The terminal type has to match the screen(console) you are using. Sometimes, if the terminal type is incorrect, the termimal escape-codes (cursor control eg.) are unrecognised by the terminal/console so the screen output is messed up. Other standaard terminal type are "vt100", "vt220".

edited Aug 29 '17 at 10:16

answered Aug 29 '17 at 10:14

Martie

1

echo $TERM gives xterm-256color – Bananach Aug 29 '17 at 10:16
and I am using the GNOME Terminal – Bananach Aug 29 '17 at 10:17
from your config file:
check the window size after each command and, if necessary,

update the values of LINES and COLUMNS.

shopt -s checkwinsize

do the echo $LINES and echo $COLUMNS values actualy match your screensize?
– Martie Aug 29 '17 at 10:22
the values of $COLUMNS and $LINES are (80,24) and I set my terminal to exactly that size using the command bar – Bananach Aug 29 '17 at 10:31

score -2 · Answer 4 · answered Apr 07 '20 at 19:36

-2

Change

TERM=xterm-256color

to

TERM=xterm

answered Apr 07 '20 at 19:36

Brian Fitzgerald

1

bash: messed up display for long lines

4 Answers4

check the window size after each command and, if necessary,

update the values of LINES and COLUMNS.