Shell Programming and Scripting

#!/bin/sh
FIFO=/tmp/__scriptname_$(date +%F)_$$
rm $FIFO >/dev/null 2>/dev/null
mkfifo $FIFO
sh $FIFO &
tr 'a-zA-Z' 'n-za-mN-ZA-M' >$FIFO <<EOF_EOF

# BEGIN of encrypted script
#!/ova/fu

rpub "Tbbq zbeavat"
rpub "Tbrqrazbetra"
rpub "Thgragnt"
rpub "Ohrabf qvnf"
rpub "Nybun"

# END of encrypted script

EOF_EOF
rm $FIFO >/dev/null 2>/dev/null

tr 'a-zA-Z' 'n-za-mN-ZA-M' <<EOF_EOF >$FIFO

tr 'a-zA-Z' 'n-za-mN-ZA-M' <<EOF_EOF | sh /dev/stdin

tr 'a-zA-Z' 'n-za-mN-ZA-M' <<EOF_EOF | sh

openssl enc -aes-256-cbc -a | openssl enc -base64 -a

openssl enc -d -base64 -a | openssl enc -d -aes-256-cbc -a

$ echo 'rpub "Tbbq zbeavat"' | tr 'a-zA-Z' 'n-za-mN-ZA-M'
rpub "Tbbq zbenvnt"
$ echo 'rpub "Tbbq zbeavat"' | tr '[a-z][A-Z]' '[n-z][a-m][N-Z][A-M]'
echo "Good morning"
$

#!/bin/sh
tr 'a-zA-Z' "some-encryption-key" <<EOF_EOF | sh /dev/stdin |
#!/ova/fu
*encrypted script goes here*
EOF_EOF

$ cat test2
#! /bin/sh
while : ; do
$ ./test2
./test2: syntax error at line 3: `end of file' unexpected
$