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 SUNOS
newgrp
newgrp(1) User Commands newgrp(1)NAME
newgrp - log in to a new group
SYNOPSIS
Command
/usr/bin/newgrp [ -| -l] [group]
sh Built-in
newgrp [argument]
ksh Built-in
*newgrp [argument]
DESCRIPTION
Command
The newgrp command logs a user into a new group by changing a user's real and effective group ID. The user remains logged in and the cur-
rent directory is unchanged. The execution of newgrp always replaces the current shell with a new shell, even if the command terminates
with an error (unknown group).
Any variable that is not exported is reset to null or its default value. Exported variables retain their values. System variables (such as
PS1, PS2, PATH, MAIL, and HOME), are reset to default values unless they have been exported by the system or the user. For example, when a
user has a primary prompt string (PS1) other than $ (default) and has not exported PS1, the user's PS1 will be set to the default prompt
string $, even if newgrp terminates with an error. Note that the shell command export (see sh(1) and set(1)) is the method to export vari-
ables so that they retain their assigned value when invoking new shells.
With no operands and options, newgrp changes the user's group IDs (real and effective) back to the group specified in the user's password
file entry. This is a way to exit the effect of an earlier newgrp command.
A password is demanded if the group has a password and the user is not listed in /etc/group as being a member of that group. The only way
to create a password for a group is to use passwd(1), then cut and paste the password from /etc/shadow to /etc/group. Group passwords are
antiquated and not often used.
sh Built-in
Equivalent to exec newgrp argument where argument represents the options and/or operand of the newgrp command.
ksh Built-in
Equivalent to exec to/bin/newgrp argument where argument represents the options and/or operand of the newgrp command.
On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways:
1. Variable assignment lists preceding the command remain in effect when the command completes.
2. I/O redirections are processed after variable assignments.
3. Errors cause a script that contains them to abort.
4. Words, following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a vari-
able assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation are not
performed.
OPTIONS
The following option is supported:
-l | - Change the environment to what would be expected if the user actually logged in again as a member of the new group.
OPERANDS
The following operands are supported:
group A group name from the group database or a non-negative numeric group ID. Specifies the group ID to which the real and
effective group IDs will be set. If group is a non-negative numeric string and exists in the group database as a group name
(see getgrnam(3C)), the numeric group ID associated with that group name will be used as the group ID.
argument sh and ksh only. Options and/or operand of the newgrp command.
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables that affect the execution of newgrp: LANG, LC_ALL, LC_CTYPE, LC_MES-
SAGES, and NLSPATH.
EXIT STATUS
If newgrp succeeds in creating a new shell execution environment, whether or not the group identification was changed successfully, the
exit status will be the exit status of the shell. Otherwise, the following exit value is returned:
>0 An error occurred.
FILES
/etc/group system's group file
/etc/passwd system's password file
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO login(1), ksh(1), set(1), sh(1), intro(3), getgrnam(3C), group(4), passwd(4), attributes(5), environ(5), standards(5)SunOS 5.10 1 Feb 1995 newgrp(1)