path

#!/bin/bash
# get a file's absolute path, function similar with linux command "readlink -f $filename"
# usage: path $filename
# source from: https://stackoverflow.com/questions/1055671/how-can-i-get-the-behavior-of-gnus-readlink-f-on-a-mac
# created by zhouwei on 2017-10-10

if [[ $# < 1 ]]; then
    echo "Usage: path \$filename"
    exit 1
fi

set -e
TARGET_FILE=$1
ls $TARGET_FILE > /dev/null

cd `dirname $TARGET_FILE`
TARGET_FILE=`basename $TARGET_FILE`

# Iterate down a (possible) chain of symlinks
while [ -L "$TARGET_FILE" ]
do
    TARGET_FILE=`readlink $TARGET_FILE`
    cd `dirname $TARGET_FILE`
    TARGET_FILE=`basename $TARGET_FILE`
done

# Compute the canonicalized name by finding the physical path 
# for the directory we're in and appending the target file.
PHYS_DIR=`pwd -P`
RESULT=$PHYS_DIR/$TARGET_FILE
echo $RESULT