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Re: Change PS1 when running as administrator

On 06/17/2014 10:21 AM, Ernie Rael wrote:
> On 6/17/2014 1:45 AM, GrahamC wrote:
>> If we are looking for other alternatives the GROUPS environment
>> variable can also be used:
>> PS1='\[\e]0;\w\a\]\n\[\e[32m\]\u@\h \[\e[33m\]\w\[\e[0m\]\n\$ '
>> for G in "${GROUPS[@]}"; do
>>      if [ "$G" = 544 ]; then
>>          PS1='\[\e]0;Administrator \w\a\]\n\[\e[32m\]\u@\h
>> \[\e[33m\]\w\[\e[0m\]\n# '
>>      fi
>> done
> Speaking of alternatives,
> For matching in bash, something like
>     [[ $(id -G) =~ \b544\b ]]

\b is a glibc regex() extension, not supported in Cygwin regex

Cygwin supports \< as a shortcut for [[:<:]], and \> as a shortcut for
[[:>:]], which are both BSD extensions.  \b is roughly equivalent to
[[:<:][:>:]] - but someone would have to actually patch cygwin's
regcomp.c to enable that extension.

> was suggested (the suggestion used symbolic name instead of a number and
> didn't use word boundary). Seems like word boundary is needed, but I
> couldn't get this to work. Are the regex boundary matchers not
> supported  by bash =~ operator?

bash only supports what the libc regex() supports, and since Cygwin
regex() is not as full-featured as glibc regex(), the answer is that you
can't use \b in Cygwin bash (yet; PTC).

Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library

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