bash PATH manipulation functions

bashstuff (text/plain), 4.53 KB, created by Aron Griffis (RETIRED) on 2003-04-05 07:45:22 UTC

# $Id: bashrc,v 1.10 2003/03/14 21:17:47 agriffis Exp $
#
# This file contains the base configuration.  This file is read for
# both login shells (via .bash_profile) and non-login shells.  Note
# that it returns halfway through for non-interactive shells.


# This configuration is dependent on the functions from .bashrc.funcs.
# None of the other .bashrc.* files are truly necessary and their
# absence will not generate errors.
. $HOME/.bashrc.funcs


#######################################################################
# Non-interactive settings
#######################################################################

# Load /etc/profile to pick up system environment changes,
# however this will load PS1 which erases our ability to detect a
# non-interactive shell.
[ -n "$PS1" ] && _interactive_shell=1
. /etc/profile

# PATH
# ----

frontpath PATH \
  /usr/local/bin /usr/local/sbin \
  /usr/bin/mme \
  /usr/bin /bin \
  /usr/sbin /sbin \
  /usr/dt/bin /usr/bin/X11 /usr/X11R6/bin /usr/bin/X11/demos \
  /usr/bin/mtools /usr/ucb /etc /usr/etc /usr/games
[ "$HOME" = / ] || frontpath PATH $HOME/bin

# remove . security hole from PATH, added by some foolish sysadmins
rmpath PATH .

# fix for POSIX.2 idiocy that assumes you mean . when there's an empty
# element in PATH
rmpath PATH ''
export PATH

# All done if non-interactive
[ "$_interactive_shell" = 1 ] || return
unset _interactive_shell        # don't need this anymore


#######################################################################
# Below actually lives in my .bashrc.funcs.  I didn't include the
# whole thing because much of it is specific to other operating
# systems where I work.  Also, only frontpath and rmpath are used
# above.
#######################################################################

# syntax: inpath PATHvar element
# example:
#     if inpath PATH /usr/bin; then
#       echo "Your PATH contains /usr/bin"
#     fi
inpath() {
  local curpath
  eval curpath=\$$1
  case "$curpath" in
    $2|$2:*|*:$2|*:$2:*) return 0 ;;
    *) return 1 ;;
  esac
}


# rmpath uses some bash2 specific features... so provide
# a bash1 compatibility version.
if [ ${BASH_VERSION%%.*} -ge 2 ]; then

  # syntax: rmpath PATHvar element1 [ element2 ... ]
  # example:
  #     rmpath MANPATH /usr/local/man
  rmpath() {
    local newpath e PATHvar
    PATHvar=$1
    eval newpath=\$$1
    shift
    for e in "$@"; do 
      newpath=${newpath/#$e:}
      newpath=${newpath//:$e:/:}
      newpath=${newpath/%:$e}
      [ "$newpath" = "$e" ] && { newpath=; break; }
    done
    eval $PATHvar=\$newpath
  }

else # bash1 compatibility

  # syntax: rmpath PATHvar element1 [ element2 ... ]
  # Remove all occurences of each element from PATHvar
  rmpath() {
    local newpath e PATHvar
    PATHvar=$1
    eval newpath=\$$1
    shift
    for e in "$@"; do 
      while true; do
	case "$newpath" in
	  $e:*) newpath="${newpath#$e:}" ;;
	  *:$e) newpath="${newpath%:$e}" ;;
	  *:$e:*) newpath="${newpath%%:$e:*}:${newpath#*:$e:}" ;;
	  $e) newpath=; break 2 ;;  # all the way out
	  *) break ;;
	esac
      done
    done
    eval $PATHvar=\$newpath
  }

fi # end bash1 compatibility


# syntax: frontpath PATHvar element1 [ element2 ... ]
# Remove all occurences of each element, then prepend elements
frontpath() {
  local e oldpath newpath PATHvar
  PATHvar=$1
  eval oldpath=\$$PATHvar
  newpath=
  shift
  rmpath oldpath $*
  for e in "$@"; do
    newpath="$newpath${newpath:+:}$e"
  done
  eval $PATHvar='$newpath${oldpath:+:}$oldpath'
}


# syntax: addpath PATHvar element1 [ element2 ... ]
# Remove all occurences of each element, then append elements
addpath() {
  local e oldpath newpath PATHvar
  PATHvar=$1
  eval oldpath=\$$PATHvar
  newpath=
  shift
  rmpath oldpath $*
  for e in "$@"; do
    newpath="$newpath${newpath:+:}$e"
  done
  eval $PATHvar='$oldpath${oldpath:+:}$newpath'
}


# syntax: cleanpath PATHvar
# Clean up PATHvar by removing duplicate elements and doubled slashes
cleanpath() {
  local e oldpath newpath PATHvar _IFS
  PATHvar=$1
  eval oldpath=\$$PATHvar
  # Get rid of doubled slashes
  while true; do 
    case "$oldpath" in
      *//*) oldpath=${oldpath%%//*}/${oldpath#*//} ;;
      *) break ;;
    esac
  done
  # Remove duplicate elements
  _IFS="$IFS"; IFS=':'
  for e in $oldpath; do
    # Remove trailing slash; the ? is to prevent removal of root dir!
    case "$e" in
      *?/) e="${e%/}" ;;
    esac
    # Append to newpath if not seen yet
    case "$newpath" in
      $e|$e:*|*:$e|*:$e:*) continue ;;
      *) newpath="$newpath${newpath:+:}$e" ;;
    esac
  done
  IFS="$_IFS"
  eval $PATHvar='"$newpath"'
}