Unfortunately this will change the value of $? if you were wanting to depend on it later...
Command substitution never affects the value of $?, and that's the only way to execute anything from within the prompt string.
I don't think it's possible to cause the expansion of PS1 to alter the value of $?. If you (or anyone else) knows of a way, I'd appreciate knowing about it.
Quote:
Originally Posted by kristinu
My problem is that if I just press enter, I do not want to have the ✗ printed.
Since you neglected to be specific, I'm assuming this is for bash.
It seems like what you need is a way to detect when no command was entered at the prompt. Bash makes available the command number through the escape sequence \#. This value (at least with the version with which I tested) is not incremented for a null command. Testing its current value against its value at the time of the previous prompt's expansion should be sufficient to make a determination.
Since any variables set in the command substition subshell are lost when the shell exists, and since environmental changes cannot propagate from a child to a parent, the only way to store the command number for future inspection is to write it to a file.
The following example is intended only as a proof of concept. Aside from the minor inefficiency of reading a file for each prompt, it doesn't support simultaneously interactive shells (although it could, with some work and help from $$). The prompt consists simply of the exit status followed by a colon and a space. If no command was entered, regardless of the value of $?, a 0 is printed (analgous to not printing the X in your original problem statement):
Regards,
Alister
Hello
I am using Debain Potato and I changed the PS1. When I log in locally everythink is fine, except that when I enter a long row without hitting enter, then it word wraps automatically. And it does it not at the end of the row, it does it in the middle of the row!
It also does not writes... (7 Replies)
Hello there !
I am new in this Unix world and just start learning Unix. I have very simple question about changing PS1 variable (Shell Prompt)
i have local.profile file in my working directory, i open in vi edit mode and add this line PS1="Hello:>" and i save that file.
I disconnected from... (2 Replies)
I want to set my prompt to something more descriptive than a plain old $, so I set the PS1 variable as such:
PS1=""
Which changes the prompt correctly, but when I change directories, it does not update the prompt. So I tried this:
PS1="`pwd`>"
I get the same results when changing... (2 Replies)
can anyone tell me how to change the $ prompt by calling a variable.
Say for example i called a var 'enable' I and would like the $ prompt to change to a phrase like 'my prompt' any help would be great (1 Reply)
please advise what's wrong with this command ?
PS1="`hostname`:`who am i | cut -d " " -f1`:>>"
trying to make the PS1 prompt look like :
machine_name:username:>>
thank you (4 Replies)
I am 100% new to Unix and trying to learn.
This is my first time even touching a script in Unix.
We have the following variable script that I am trying to run....
##################################
###### variable test###
##################################
Hostname=`hostname`... (3 Replies)
Ok then i Have a challenge for you :
Give me PS1 so that it always display the least 2 levels of directory
(except if i am above of course)
I want it this way :
so if i go to
/
/home/
/home/user
/home/user/whatever
/home/user/whatever1/whatever2
my PS1 should respectively... (12 Replies)
Hi,
I am using git bash terminal window to do git operations. I have set the prompt string variable PS1 in the ~/.bashrc file as follows:
export PS1=" "
This is intended to show me the current git branch's name which is active as part of the prompt string. But, the problem is when I do a git... (2 Replies)
Hi, I need help changing PS1 in Solaris. I tried this:
MYPROMPT="> "
PS1=$LOGNAME@$HOSTNAME:${PWD}$MYPROMPT (NOT SURE WHY IT'S HIGHLIGHTED HERE)
export PS1
My problem is that $PWD is not working, when I get the prompt and I change directories, the prompt is not displaying the current... (17 Replies)
Hello I am attempting to generate a bash scrip that prompts me at loggin to change my PS1 -
However, I am running into an issue w/ the code.
#!/bin/bash
#the point of this script is to that it automates and changes my prompts every day
msg1="What do you feel like adding today :"
echo... (11 Replies)
Discussion started by: D'go
11 Replies
LEARN ABOUT ULTRIX
ppmtosixel
ppmtosixel(1) General Commands Manual ppmtosixel(1)NAME
ppmtosixel - convert a portable pixmap into DEC sixel format
SYNOPSIS
ppmtosixel [-raw] [-margin] [ppmfile]
DESCRIPTION
Reads a portable pixmap as input. Produces sixel commands (SIX) as output. The output is formatted for color printing, e.g. for a DEC
LJ250 color inkjet printer.
If RGB values from the PPM file do not have maxval=100, the RGB values are rescaled. A printer control header and a color assignment table
begin the SIX file. Image data is written in a compressed format by default. A printer control footer ends the image file.
OPTIONS -raw If specified, each pixel will be explicitly described in the image file. If -raw is not specified, output will default to com-
pressed format in which identical adjacent pixels are replaced by "repeat pixel" commands. A raw file is often an order of magni-
tude larger than a compressed file and prints much slower.
-margin
If -margin is not specified, the image will be start at the left margin (of the window, paper, or whatever). If -margin is speci-
fied, a 1.5 inch left margin will offset the image.
PRINTING
Generally, sixel files must reach the printer unfiltered. Use the lpr -x option or cat filename > /dev/tty0?.
BUGS
Upon rescaling, truncation of the least significant bits of RGB values may result in poor color conversion. If the original PPM maxval was
greater than 100, rescaling also reduces the image depth. While the actual RGB values from the ppm file are more or less retained, the
color palette of the LJ250 may not match the colors on your screen. This seems to be a printer limitation.
SEE ALSO ppm(5)AUTHOR
Copyright (C) 1991 by Rick Vinci.
26 April 1991 ppmtosixel(1)