#!/bin/bash
# º¯¼ö °£Á¢ ÂüÁ¶.

a=letter_of_alphabet
letter_of_alphabet=z

echo

# Á÷Á¢ ÂüÁ¶.
echo "a = $a"

# °£Á¢ ÂüÁ¶.
eval a=\$$a
echo "ÀÌÁ¦ a = $a"

echo


# ÀÌÁ¦ 2Â÷ ÂüÁ¶(second order reference)¸¦ ¹Ù²ãº¸µµ·Ï ÇÏÁÒ.

t=table_cell_3
table_cell_3=24
echo "\"table_cell_3\" = $table_cell_3"
echo -n "¿ªÂüÁ¶(dereferenced)µÈ \"t\" = "; eval echo \$$t
# ÀÌ °£´ÜÇÑ ¿¹Á¦¿¡¼­´Â, 
#   eval t=\$$t; echo "\"t\" = $t"
# ¶ó°í Çصµ µË´Âµ¥ ¿Ö ±×·²±î¿ä?

echo

t=table_cell_3
NEW_VAL=387
table_cell_3=$NEW_VAL
echo "\"table_cell_3\" ÀÇ °ªÀ» $NEW_VAL ·Î ¹Ù²ß´Ï´Ù."
echo "\"table_cell_3\" Àº ÀÌÁ¦ $table_cell_3 ÀÌ°í,"
echo -n "¿ªÂüÁ¶µÈ \"t\" ´Â "; eval echo \$$t
# "eval" Àº "echo"¿Í "\$$t" µÎ °³ÀÇ ÀÎÀÚ¸¦ ¹Þ¾Æ¼­ $table_cell_3 °ú ¶È°°ÀÌ ¼¼Æ®ÇØÁÝ´Ï´Ù.
echo

# (S.C. °¡ À§ µ¿ÀÛÀ» ÀÚ¼¼È÷ ¼³¸íÇØ ÁÖ¾ú½À´Ï´Ù.)


# "Bash, ¹öÀü 2" Àå¿¡¼­ ¼³¸íÇÒ ${!t} Ç¥±â¹ýµµ ¾µ ¼ö ÀÖ½À´Ï´Ù.
# "ex78.sh" ¿¹Á¦¸¦ Âü°íÇϼ¼¿ä.

exit 0