bash-shell-base/function/02-path

#!/bin/bash
path_remove () {
        local IFS=':'
        local NEWPATH
        local DIR
        local PATHVARIABLE=${2:-PATH}
        for DIR in ${!PATHVARIABLE} ; do
                if [ "$DIR" != "$1" ] ; then
                  NEWPATH=${NEWPATH:+$NEWPATH:}$DIR
                fi
        done
        export $PATHVARIABLE="$NEWPATH"
}

path_prepend () {
  path_remove $1 $2
    if ([[ -d "$1" ]] || [[ ! $1 = /* ]]); then
      local PATHVARIABLE=${2:-PATH}
      export $PATHVARIABLE="$1${!PATHVARIABLE:+:${!PATHVARIABLE}}"
    fi
}

path_append () {
  path_remove $1 $2
  if ([[ -d "$1" ]] || [[ ! $1 = /* ]]); then
    local PATHVARIABLE=${2:-PATH}
    export $PATHVARIABLE="${!PATHVARIABLE:+${!PATHVARIABLE}:}$1"
  fi
}

path_insert () {
  if ([[ -d "$1" ]] || [[ ! $1 = /* ]]); then
    local PATHVAR=${4:-PATH}
    local temp
    echo inserting $1 into ${!PATHVAR} $2 $3
    boa=$([[ $2 == b* ]] && echo "$1:&" || echo "&:$1:")
    temp="$(echo ${!PATHVAR} | sed -r "s#$3(:)?#$boa#" | sed 's#^:##' | sed 's#\:$##' | sed 's#::#:#g' )"
    echo result: $temp
    export PATHVAR=$temp
    fi
}

# path_insert_before () {
#   _path_insert b "$@"
# }
#
# path_insert_after () {
#   _path_insert a "$@"
# }