On 3/4/2019 5:16 AM, Greg Wooledge wrote:
> On Sat, Mar 02, 2019 at 08:47:43PM -0800, L A Walsh wrote:
>
>> hb=~law/bin (line#4)
>>
>
> Well, that's just a syntax error.
>
---
Sorry, the '(line#4)' was editorial commenting (vs. actual commenting)
>
>> if ! [[ $hb =~ $PATH ]]; then export PATH="$hb:$hl:$PATH"; fi
>>
>
> What is the logic behind that regex check? It looks completely wrong.
>
> If the intent of this code is "check whether $hb is already in $PATH",
> then this code is incorrect.
>
Hi Greg!
1) You're right, the order is reversed. Thank-you!
2) It usually doesn't matter in my case, since my PATH usually
contains both of those paths. (BTW, to give you an idea of why I
used these names, 'h':home, '{b,l}:{bin,lib}'.
So, probably, just reversing the order should be sufficient for my
purposes. Strictly speaking, whether or not they are in my path
is unrelated to the problem, which is another reason why I didn't pay
too much attention to it, but more than once I've reversed the order.
In scripts where this needs to be correct, I use functions that
I've written to avoid my having to remember (only used to
init the environment @ login or when .bashrc is called):
Try these for functionality (not necessarily optimal):
# if needed, uncomment:
# shopt -s bash_aliases # required for POSIX-compat shell
# alias my='declare ' int='my -i ' array='my -a ' map='my -A '
# NOTE: only handles 1 pathname at a time
# empty defined as 1) not existing, 2) for dirs: nothing in dir
# 3) for files: size 0
sub _path_empty {
my _abort=exit
[[ $0 =~ bash$ ]] && _abort=return
if (($#>1)); then
printf "FATAL internal error: _path_empty only takes 1 arg, not
%d\n" $#
[[ $0 =~ bash$ ]] && return 1; exit 1
fi
my _ng_savestate=$(shopt -p nullglob)
shopt -s nullglob
int true=0 false=1
int _empty=true
if [[ ! -e $1 ]]; then _empty=true
elif [[ -f $1 && -s $1 ]]; then _empty=false
elif [[ -d $1 ]]; then
array _entries=("$1"/*)
((${#_entries[@]})) && _empty=false
fi
$_ng_savestate
return $_empty
}
_path_has_subpath() { [[ ${!1} =~ :$2:|^$2:|:$2$ ]] ; }
# _path_op CODE ['!'] PATHVarName
# - in 'delete' case (uses '!'), status from path_has_subpath is toggled
# this means P_H_S becomes check for path NOT having subpath
# 'code' = shell script options to perform
# 'pathVarName' = "path-like" VarName (ex. PATH or LD_LIBRARY_PATH)
_path_op() {
(($#<3)) && return 1
my code=$1 pathVarName=$2; shift 2
int del=0
[[ ${pathVarName:-} == ! ]] && { del=1 ; pathVarName=$1 ; shift ; }
if ((!${#code} || !${#pathVarName})); then
echo >&2 "_path_op: bad args"; sleep 1;return 1; fi
while (($#)); do
if [[ -d $1 ]] && ! _path_empty "$1"; then
{ _path_has_subpath "$pathVarName" "$1" ; ((!($?^$del))) ; }
|| {
eval "$(set "$pathVarName" "$1"; eval "echo $code")"
}
fi
shift;
done
}
# called with name of path (ex. 'PATH' & one or more sub paths
# each of these prepend an "assign FORMAT" to the passed-in PATHVAR +
pathcomp
_path_delete() { _path_op '$1=\"${!1//@(^$2:|:$2$)|$2:/}\"' '!' "$@" ; }
_path_append() { _path_op '$1=\"${!1}${!1:+:}$2\"' "$@" ; }
_path_prepend() { _path_delete "$1" "$2"; _path_op
'$1=\"$2${!1:+:}${!1}\"' "$@" ; }
export -f _path_append _path_prepend _path_has_subpath _path_op
_path_delete _path_empty
