Append/prepend/remove a path to/from an environment variable. Assumed no spaces in the path. #bash

path-manip.bash

# append_path VAR PATH - adds PATH to the end of PATH
append_path() {
  [ $# -lt 2 ] && return
  [ ! -d "$2" ] && echo "Warning: path $2 is not found on `hostname`" >&2
  remove_path $1 $2
  if eval '[ -z "$'$1'" ]'; then
    eval $1=$2
  else
    eval $1='$'$1:$2
  fi
  export $1
}

# prepend_path VAR PATH - adds PATH to the beginning of PATH
prepend_path() {
  [ $# -lt 2 ] && return
  [ ! -d "$2" ] && echo "Warning: path $2 is not found on `hostname`" >&2
  remove_path $1 $2
  if eval '[ -z "$'$1'" ]'; then
    eval $1=$2
  else
    eval $1=$2:'$'$1
  fi
  export $1
}

# remove_path VAR PATH - removes PATH from VAR
remove_path() {
  [ $# -lt 2 ] && return
  eval $1'=${'$1'//:$2/}'
  eval $1'=${'$1'//$2:/}'
  eval '[ "$'$1'" == "'$2'" ]' && eval $1=
  export $1
}

# set_path VAR PATH - sets VAR to PATH
set_path() {
  [ ! -d "$2" ] && echo "Warning: path $2 is not found on `hostname`" >&2
  eval "$1=$2"
  export $1
}

# set_env VAR VALUE - sets VAR to VALUE
set_env() {
  [ $# -lt 1 ] && return
  eval "$1=$2"
  export $1
}

# append_path_c VAR PATH - same as append_path but without warnings
append_path_c() {
  [ -d "$2" ] && append_path "$1" "$2"
}

# prepend_path_c VAR PATH - same as prepend_path but without warnings
prepend_path_c() {
  [ -d "$2" ] && prepend_path "$1" "$2"
}

# set_path_c VAR PATH - same as set_path but without warnings
set_path_c() {
  [ -d "$2" ] && set_path "$1" "$2"
}

# split_path [VAR] - prints VAR (default: PATH) split over lines
split_path() {
  local path='$'${1:-PATH}
  path=`eval "echo $path"`
  local IFS=':'
  for p in $path; do
    echo "$p"
  done
}

# clean_path [VAR] - removes duplicates in VAR (default: PATH)
clean_path() {
  local var=${1:-PATH}
  local val=$(eval "echo \$$var" \
    | awk -v RS=: -v ORS=: '!a[$1]++{if(NR>1)printf ORS;printf $a[$1]}')
  eval "$var='$val'"
}