idea

#!/bin/sh
 
# check for where the latest version of IDEA is installed
IDEA=`ls -1d /Applications/IntelliJ\ * | tail -n1`
wd=`pwd`

# were we given a directory?
if [ -d "$1" ]; then
#  echo "checking for things in the working dir given"
  wd=`ls -1d "$1" | head -n1`
fi

# were we given a file?
if [ -f "$1" ]; then
#  echo "opening '$1'"
  open -a "$IDEA" "$1"
else
    # let's check for stuff in our working directory.
    pushd $wd > /dev/null

    # does our working dir have an .idea directory?
    if [ -d ".idea" ]; then
#      echo "opening via the .idea dir"
      open -a "$IDEA" .

    # is there an IDEA project file?
    elif [ -f *.ipr ]; then
#      echo "opening via the project file"
      open -a "$IDEA" `ls -1d *.ipr | head -n1`

    # Is there a pom.xml?
    elif [ -f pom.xml ]; then
#      echo "importing from pom"
      open -a "$IDEA" "pom.xml"

    # can't do anything smart; just open IDEA
    else
#      echo 'cbf'
      open "$IDEA"
    fi

    popd > /dev/null
fi

Whipped up a more dynamic version, which handles both toolbox and non-toolbox installed intellij apps, check it out here:
https://gist.github.com/dotCipher/9c5f7647bda088fde5dc561cc121b0a5

Idea can create a similar script for you. From in Idea,

Tools > Create Command-line Launcher...

@davidlanouette Thanks!

@davidlanouette, this is why you might consider using this script instead:
https://emmanuelbernard.com/blog/2017/02/27/start-intellij-idea-command-line/

@davidlanouette Thanks