Bash/Ruby, 104

"alias" "puts=f()(tee -;echo a);f"
puts <<a *2+"a"
"alias" "puts=f()(tee -;echo a);f"
puts <<a *2+"a"
a

Bash/Ruby, 128 without undefined behavior

"alias" 'puts=f()(a=`cat`;echo "$a
$a
a");f'
puts <<'a' *2+"a"
"alias" 'puts=f()(a=`cat`;echo "$a
$a
a");f'
puts <<'a' *2+"a"
a

Bash/Ruby, 104 82

"tee`#";puts <<a*2+'a'#`" -<<'a';echo a
"tee`#";puts <<a*2+'a'#`" -<<'a';echo a
a

Older version:

"alias" "puts=f()(tee -;echo a);f"
puts <<a *2+"a"
"alias" "puts=f()(tee -;echo a);f"
puts <<a *2+"a"
a

Bash/Ruby, 128 without undefined behavior

"alias" 'puts=f()(a=`cat`;echo "$a
$a
a");f'
puts <<'a' *2+"a"
"alias" 'puts=f()(a=`cat`;echo "$a
$a
a");f'
puts <<'a' *2+"a"
a