Re: Change PS1 when run as administrator

[Thomas Wolff]

Am 15.03.2016 um 18:08 schrieb Corinna Vinschen:
On Mar 15 12:33, Andrew Schulman wrote:
I just came up with this recipe to change the default PS1 value to use red for 
the user@host part of the prompt and to change the $ character to a #:
     if id | grep -qi 'member of administrators group'
     then
         export PS1=$(echo "$PS1" | sed -e 's_32_31_' -e 's_\\\$_#_')
     fi

I’m not certain the string match on the output of id(1) works everywhere.  Is 
there a better way to check for admin privileges under Cygwin?  You can’t check 
for UID or EUID == 0, for example, as you’d do on a true POSIX system.
Ha!  Yes, there is:  see
https://cygwin.com/ml/cygwin/2015-02/msg00057.html.  The magic test is

id -G | grep -qE '\<(544|0)\>'

where 544 is the Administrators group, and 0 is the root group in case the
old root group entry is present in /etc/group.

For example:

id -G | grep -qE '\<(544|0)\>' && echo admin || echo user
Thou shalt not use the test for gid 0 anymore.  If it works, remove the
entry from /etc/group, or better, remove /etc/group entirely.  This entry
will render wrong and unwanted results when you least expect them.  Such
cruft always does.
So id -G | grep -q '\<544\>' I suppose. Is there also a universal 
replacement for
    elif id | grep -e "gid=.*(Power Users)" > /dev/null
?
Thomas

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