Is the file in question a soft or hard link to this other file?

IsLinked.sh

#!/bin/sh

## @author  Jay Goldberg
## @email  jaymgoldberg@gmail.com
## @license  Apache 2.0
## @description  Determine if a file is a symlink or hardlink to a particular file
##              Example, "is this file a hard or softlink to Busybox?
## @usage  source it, then IsLinked <possible_link> <target>
#=======================================================================

IsLinked() {
  # TODO what if `which` doesn't exist? `which` is actually a shell script
  [ ! "$#" -eq 2 ] && { echo "wrong argument count" >&2; return 4; }
  local destexe="$(which $2)"
  local exe="$(which $1)"
  
  [ ! -f "$destexe" ] || [ ! -e "$exe" ] && { echo "some of the paths do not exist" >&2; return 1; }

  # is $exe a symlink?, if so, is it pointing to $destexe?
  if [ -L "$exe" ] && [ "$(basename $(readlink $exe))"  = "$(basename $destexe)" ]; then
    echo "true"
  # is it a hardlink to $destexe?
  # TODO: what if `stat` is not available? (ls -i $exe | cut -d' ' -f1)
  elif [ "$(stat -c %i $exe)" = "$(stat -c %i $destexe)" ]; then
    echo "true"
  else
    echo "false"
  fi
}

_Test_IsLinked() {
  local EXITCODE=0
  local destexepath="ls_target"
  local sourceexe="ls_link"
  
  touch "$destexepath" || { echo "unable to create test target"; return 1; }
  chmod u+x "$destexepath" || { echo "unable to mark test target as executable"; return 1; }
  export PATH="./:$PATH"
  
  rmfiles() { [ -e "$sourceexe" ] && rm "$sourceexe"; }; rmfiles
  
  echo "create softlink"
  ln -s "$destexepath" "$sourceexe" || { echo "unable to create softlink"; return 1; }
  echo " >>> is it a softlink?"
  [ $(IsLinked "$sourceexe" "$destexepath") == "true" ] && echo "PASS"
  rmfiles
  
  echo "create hardlink"
  ln "$destexepath" "$sourceexe" || { echo "unable to create hardlink"; return 1; }
  echo " >>> is it a hardlink?"
  [ $(IsLinked "$sourceexe" "$destexepath") == "true" ] && echo "PASS"
  rmfiles
  
  touch "$sourceexe"
  echo "bogus link?"
  IsLinked "$sourceexe" "$destexepath" || echo "PASS"
  rmfiles
  
  rm "$destexepath" || echo "unable to delete test file"
  
  return $EXITCODE
}