How do I get Cygwin xterm to use bash and not sh? - cygwin

Just updated cygwin to 1.7.28 on Windows 7.
Previously when starting X, the xterm would open with bash. For some reason it is now opening with sh?
What configuration changes do I need to make so that bash is the default shell again?
Not sure why this change happened.
The shortcut to open the xterm is the same as it was during my initial installation.
C:\cygwin\bin\run.exe /usr/bin/bash.exe -l -c /usr/bin/startxwin.exe
But it still starts with the default shell set to sh.
I don't understand what changed.
My passwd file is the same as it was before.
It appears that everything starts fine with the standard shortcuts, but the X and xterm startups are not sourcing /etc/profile

I had /etc/shells already (upgraded from ??? to 1.7.29), might have been new with upgrade, but still didn't work (xterm running sh instead of bash). Changed permissions on bash to fix.
It was 700 changed to 755
chmod 755 /bin/bash

xterm seems to need the /etc/shells file to be present to work. Add an /etc/shells file with the following contents:
# /etc/shells: valid login shells
/bin/csh
/bin/sh
/bin/bash
/bin/tcsh
/usr/bin/csh
/usr/bin/sh
/usr/bin/bash
/usr/bin/tcsh
Chris

Run following command to set bash as default shell.
set shell=C:/cygwin/bin/bash
Note path C:/cygwin/bin/bash may vary.

(Removed answer regarding /etc/passwd)
I tried your command on my cygwin and got the same behavior, i.e. xterm loaded with /bin/sh.
However, if I simply ran startxwin.exe directly, I get an xterm loaded with /bin/bash.
Dunno if this works for you, but, worth a try.

I had the same issue with sh launching, but managed a different workaround after having issues with /etc/shells
I also wanted to get rid of the default white /bin/sh xterm that startxwin.exe created.
It turns out there's a .startxwinrc that startxwin.exe sources, so I had it do this:
# Launch prettier xterms with bash
. ./.profile
# Exit the cruddy white xterm launched by startxwin
exit
The dot-space syntax above is equivalent to "source" in bash, but is more shell-independent.

Related

How to Change my default shell on server?

I was assigned an account for log in to a remote server, and I want to change my default shell.
I tried chsh command but it says: chsh: "/public/home/{my_id}/bin/zsh" is not listed in /etc/shells.
If you don't have permission to install zsh system wide, a quick fix is to append exec ~/bin/zsh -l to ~/.bash_profile (if bash is the current shell), or an equivalent rc file for the current login shell.
zsh -l starts zsh as a login shell.
exec COMMAND replaces the current process with COMMAND, so you'll only have to type exit (or press ctrl+d) once.
~/.bash_profile is executed when bash starts as a login shell, you can still run command bash normally.
Depending what is in ~/.bash_profile (or equivalent), you may wish to avoid executing its other contents, by putting exec ~/bin/zsh -l at the start of the file (not the end), and copy/port anything important over to the zsh equivalent, $ZDOTDIR/.zprofile.
I might also do export SHELL="$HOME/bin/zsh", although I'm unsure of the full effects of setting SHELL differently to that specified for your user in /etc/passwd, to a shell not in /etc/shells, and to a shell binary in your home path.
First check all the shells available on your linux system
cat /etc/shells
Use chsh command line utility for changing a login shell with the -s or –shell option like this.
# chsh --shell /bin/sh tecmint

bash changing directory when started

I have both Bash on Ubuntu on Windows and Cygwin bash installed on my machine, and both are setup to have the same ~ folder (via /mnt/c/source and /cygdrive/c/source respectively).
When I start Ubuntu's bash prompt via bash --login -i (or just bash --login) from any directory, I get a prompt running from within that directory; however, when I start Cygwin's bash via the same command, the current directory is overridden, and the prompt is always at ~. See the screenshots for a simple example.
My user directory's .bashrc and .bash_profile are of course the same, as both are using the same user directory. I've looked into Cygwin's /etc/bash.bashrc and there doesn't seem to be anything there to change my current directory, and there aren't any other relevant files in /etc.
What could be causing Cygwin's bash to change directory?
you just add a command "cd /dir_you_want" at the bottom of ~/.bashrc in cygwin
I've figured it out, so in case anyone runs into the same issue:
There's one file I neglected to look into, because I didn't know it exists, /etc/profile. In Cygwin, by default it has the following section in it:
# Make sure we start in home unless invoked by CHERE
if [ ! -z "${CHERE_INVOKING}" ]; then
unset CHERE_INVOKING
else
cd "${HOME}" || echo "WARNING: Failed attempt to cd into ${HOME}!"
fi
Disabling that solves the issue of course.

Writing a Script to execute commands?

I have never written a script, so bear with me. What I need to do, is make two scripts that I can click on from the desktop, will both open their own terminal (And stay open until I manually close it) and run the given lines.
For the first one, I have to manually run this:
cd home/pi/PiBits/ServoBlaster/user
sudo ./servod
For the second:
cd ~/scratchClient
python crs/scratchClient.py -c servoblaster
How would I do this? I read a few things about putting xterm -e and such in front of it, but none of that works for me...
By the way, this will be used on Raspbian Linux.
EDIT, this worked for me:
Link: ubuntuforums.org/showthread.php?t=1336228 The line that was used: gnome-terminal --execute bash -c "/path/scriptname ; bash"
You just need to add a shebang, which means putting this in the first line of the script:
#!/bin/sh
This causes the bourne shell to be used to interpret the script, this is (probably) the same interpreter that runs when you are in your terminal. Then you should make the script executable chmod +x <script>
Try this.
xterm -hold -e 'cd /home/pi/PiBits/ServoBlaster/user
sudo ./servod' &
and
xterm -hold -e 'cd /home/pi/scratchClient
python crs/scratchClient.py -c servoblaster' &
If it doesn't work, perhaps you should explain in what way this fails. If it works, you can add a shebang in front, save them in files, chmod +x those files, and click away to your heart's content (or perhaps acquire a more sophisticated taste where you simply run these as background jobs without any xterm or other anxious GUI).
Solution was to use gnome-terminal... Found an UbuntuForums post with a similar question such as mine.
gnome-terminal --execute bash -c "/path/scriptname ; bash"

Bash: Invalidated commands

I've incurred a worrisome issue with my bash shell. I was editing my bash_profile and accidentally exported an incomplete command (export PATH=/usr/local/bin). After I had reloaded my terminal, nearly all of my bash commands fail to work properly. When I try to run any one of them, the errors state: command not found.
How do I fix this? Is there an alternate way to open or find my bash_profile?
I would appreciate any immediate input I can get on this issue. Thank you in advance.
You can execute commands if you can give the directory name. Almost all the basic Unix commands are under the /bin or /usr/bin directory. For example, /bin/mv.
Fortunately, builtin commands are still recognizable.
Move your .bash_profile and .bashrc file out of the way for now, and see what the system default is.
You can manually edit your PATH on the command line to:
$ PATH="/bin:/usr/bin"
$ cd
$ mv .bash_profile .bash_profile.bak
$ mv .bashrc .bashrc.bak
$ mv .profile .profile.bak
$ mv .bash_login .bash_login.bak
NOTE: Some of these mv command may fail simply because that particular file may not exist.
which will give you access to most of the basic Unix commands. Or you can specify the commands with their full directory names:
$ PATH="/bin:/usr/bin"
$ cd
$ /bin/mv .bash_profile .bash_profile.bak
$ /bin/mv .bashrc .bashrc.bak
$ /bin/mv .profile .profile.bak
$ /bin/mv .bash_login .bash_login.bak
Now, log in again and see what your default $PATH is set to. This is set by the /etc/profile. You might find that's just fine, and remove setting PATH in your startup script.
The standard for PATH is something like this:
/usr/share/bin or /usr/local/bin - These contain non-standard Unix/Linux commands. For example, if you install Maven on your system, the mvn command will usually be located in one of these directories (maybe as a symbolic link). This directory is a place where commands not found in the /bin and /usr/bin directory are stored. This directory is first, so you can replace the version which came with your system with more recent versions. For example, I might have VIM 6.4 installed, but I want to use version 7.3 instead.
/bin:/usr/bin - The standard directories where 99% of the Unix commands live.
$HOME/bin - These are executables you wrote -- either scripts or binaries. This is at the end of the PATH list because it makes sure that you don't accidentally execute the wrong version of the command. Imagine if some joker wrote a shell script called cp that executed /bin/rm instead and placed it in your $HOME/bin directory.
Other directories you'll see may include /sbin/ and /usr/sbin which are administrator commands (ping and ifconfig are sometimes in one of these directories.) /opt/bin/X11 (or wherever the X11 binaries are stored). Sometimes other commands will futz around with your PATH, for example Perlbrew.
#fedorqui's comment provides a quick fix.
The OP could also have used the following to quickly get to a shell with default values for $PATH:
To create a bash shell with a pristine default environment:
without running profile/initialization scripts
without inheriting any environment variables from the current shell
run:
/usr/bin/env -i bash --norc
Note:
Due to use of env's -i option, many environment variables that are normally set will NOT be set in the resulting shell , such as USER, HOME and LANG.
Similarly, the $PATH value you'll get is presumably one hard-coded into bash itself, but it should provide access to at least the standard utilities.
--norc suppresses loading of ~/.bashrc, which normally happens by default for interactive non-login bash shells (bash also supports the --noprofile option to suppress loading of /etc/profile and ~/.bash_profile, but it doesn't apply here, since the shell created is a non-login shell).
If env is in the current shell's $PATH, env -i bash --norc will do.
env is in /usr/bin/ on at least Linux and on FreeBSD/OSX, probably also on other platforms.

How can I debug the bash prompt?

I've been editing .bashrc files and other init files, and it seems that I've left behind a few code snippets or two that are causing a few errors at the prompt (e.g. file missing), but I can't find them.
How do I debug the prompt to find out what init scripts I've carelessly hacked?
Most of the shells have debug flags that show the commands being executed. Bash may even have one that shows a command before expansion of variables and after. Have you tried checking (I believe) -c -x or -X flags and see if they show the information you are looking for.
You can set them as first thing in the rc files (most global one) or just pass it down into bash command by invoking it from another shell.
In fact, if you invoke bash from another shell, you can also use script command to record everything you see and do into the file, which makes postmortem analysis so much easier.
Try invoking bash with the -x flag, then sourcing your .bashrc or .bash_profile or whatever you're using. That ought to be prolix enough to find your problem
ie:
bash -x
source .bashrc
The easiest way to get a clean initial state is to SSH into your current host, but instead of letting SSH launch your shell with default settings, you provide an explicit command which prevents .bashrc from being read.
ssh -tt localhost /bin/bash --norc
The -tt forces SSH to allocate a TTY, which is what would normally happen when you open a shell connection, but is not default when running an explicit command.
The --norc prevents bash from reading your settings file (since we want to do that ourselves).
You should now be at a bash prompt, in a clean environment. This is useful for examining what variable are set to before your .bashrc runs etc. Enable tracing and source your .bashrc:
set -x # Enable tracing
source .bashrc
Try to see where you've defined prompt - probably it in some dot file in your home directory:
grep PS1 ~/.*
You can see current value of prompt by just printing it:
echo $PS1
HTH
Check the .bash_history file in your home directory to find out what commands you have been running. If you used commands like vi filename to open the init scripts, it will find them in the command history.

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