Prompt erases line

Prompt erases line

[Le Wang]

Hi all,

The zsh propmpt always seem to erase the line if the
line does not end in a "\n"

-----
lewang@phobe ~ % echo asdf
asdf
lewang@phobe ~ % echo -n adsf
lewang@phobe ~ %
-----

Is there any way to get it to just print the prompt
after the text on the same line?


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Re: Prompt erases line

[Deborah Ariel Pickett]

> The zsh propmpt always seem to erase the line if the
> line does not end in a "\n"
> -----
> lewang@phobe ~ % echo asdf
> asdf
> lewang@phobe ~ % echo -n adsf
> lewang@phobe ~ %
> -----
> Is there any way to get it to just print the prompt
> after the text on the same line?

unsetopt PROMPT_CR

This is assuming that you don't have a carriage return character in your
PS1 shell variable.

Put it in your $HOME/.zshrc file if you want it to behave that way every
time you start a shell.

Be aware that unsetting PROMPT_CR can cause some unusual behaviour with
the zle editor, because it has no way of knowing how many characters
have already been printed on the line before the prompt.

<digression>

On an aside, I used to have the following code in my precmd function,
which would detect if the cursor wasn't up against the left edge of the
screen using an xterm/VT100 escape sequence.  If the cursor wasn't in
the first column, the precmd function would print a message and arrange
for the prompt to be printed anew on the line below.

It was a cute feature, but I've since disabled it because it was too
slow to use seriously, and timing issues meant that it didn't always
work across a slow (dialup) connection.  It would have worked a bit
quicker if the "STTY='opts' command" trick worked on the print/read
combination in the middle of the report-cursor-position function (thus
removing two fork/execs to the external stty command), but I couldn't
make it work.

Besides, the whole thing was pretty useless, to be honest.

To use it, set PROMPTCURSORPOS to a number such as 10.  This is the
number of milliseconds the function waits for a response from the
terminal driver.


# report-cursor-position
# Returns the horizontal cursor position for xterms and other terminals.
# The returned number is zero-origin, so a "successful" (in shell terms)
# return means the cursor is at the left edge of the screen.
#
# This code is lifted from an example in the xterm FAQ
# written by Icarus Sparry <icarus@bath.ac.uk> 11 Apr 1997
# and modified to use a different control sequence.

report-cursor-position()
{
  
  local old a
  
  if [[ $TERM = xterm* ]]
  then
    # Send the terminal the code and wait for its response.
    exec </dev/tty
    old=$(stty -g)
    stty raw -echo min 0  time ${1-10}
    print -n "\e[6n" > /dev/tty
    IFS='' read -r a
    stty $old
  
    a=${${a##*;}%%R*}
    return $(( $a - 1 ))
  fi
}

precmd()
{
# .... other stuff ...
  # Check the cursor position - is it up against the left margin?
  # This can be kind of slow, so we only do it if a shell variable is
  # set (which it isn't by default - see below).
  if [[ ${+PROMPTCURSORPOS} -eq 1 ]]
  then
    # This function works on xterms and other assorted terminals
    # by querying the terminal for its cursor position.  It returns zero
    # if the cursor is in the leftmost position, nonzero otherwise.
    if ! report-cursor-position $PROMPTCURSORPOS
    then
      print "[no newline]"
    fi
  fi
# .... other stuff ...
}

</digression>

-- 
Debbie Pickett http://www.csse.monash.edu.au/~debbiep debbiep@csse.monash.edu.au
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