Source code in the unix programming language

#!/bin/sh
cat << ANARBITRARYTOKEN
The river was deep but I swam it, Janet.
The future is ours so let's plan it, Janet.
So please don't tell me to can it, Janet.
I've one thing to say and that's ...
Dammit. Janet, I love you.
ANARBITRARYTOKEN


cat << EOF
Here documents do parameter and command substitution:
 * Your HOME is $HOME
 * 2 + 2 is `expr 2 + 2`
 * Backslash quotes a literal \$, \` or \\
EOF


if true; then
    cat <<- EOF
    The <<- variant deletes any tabs from start of each line.
    EOF
fi


cat << 'TOKEN'
If TOKEN has any quoted characters (like 'TOKEN', "TOKEN" or \TOKEN),
then all $ ` \ in the here document are literal characters.

$PATH \$PATH `shutdown now`
TOKEN


echo '
In any unix shell, you specify a text block and can use all whitespace like
  (spaces) &    (tab) in it, by using single quotes. 
As mentioned above, a Unix "here document" is a type of redirection.
In a literal Bash here document, the starting token must be
quoted, but the end token must not, so they are not the same, which does not
conform to the task definition.
'


#!/bin/csh -f
cat << ANARBITRARYTOKEN
 * Your HOME is $HOME
 * 2 + 2 is `@ n = 2 + 2; echo \$n`
ANARBITRARYTOKEN

cat << 'ANARBITRARYTOKEN'
$PATH \$PATH `shutdown now`
'ANARBITRARYTOKEN'