Generate script in bash and save it to location requiring sudo

Question

In bash I can create a script with a here-doc like so as per this site: http://tldp.org/LDP/abs/html/abs-guide.html#GENERATESCRIPT

(
cat <<'EOF'
#!/bin/bash
#? [ ] / \ = + < > : ; " , * | 
#/ ? < > \ : * | ”
#Filename="z:"${$winFn//\//\\}
echo "This is a generated shell script."
App='eval wine "C:\Program Files\foxit\Foxit Reader.exe" "'$winFn'"'
$App
EOF
) > $OUTFILE

If my $OUTFILE is a directory requiring sudo privileges where do I put the sudo command or what else can I do to make it work?

Answer 1

This is how I would do it:

sudo tee "$OUTFILE" > /dev/null <<'EOF'
foo
bar
EOF

Answer 2

Just putting sudo before cat doesn't work because >$OUTFILE attempts to open $OUTFILE in the current shell process, which is not running as root. You need the opening of that file to happen in a sudo-ed subprocess.

Here's one way to accomplish this:

sudo bash -c "cat >$OUTFILE" <<'EOF'
#!/bin/bash
#? [ ] / \ = + < > : ; " , * | 
#/ ? < > \ : * | ”
#Filename="z:"${$winFn//\//\\}
echo "This is a generated shell script."
App='eval wine "C:\Program Files\foxit\Foxit Reader.exe" "'$winFn'"'
$App
EOF

This starts a sub-shell under sudo, and opens $OUTFILE from that more privileged subprocess, and runs cat (as yet another privileged subprocess). Meanwhile, the (less privileged) parent process pipes the here-document to the sudo subprocess.

Answer 3

You can also use dd for that:

sudo dd of="$OUTFILE" <<EOF
foo
bar
EOF

Answer 4

None of the answers expanded environment variables since they use the subtle feature "Parameter substitution turned off" as described in: tldp.org/LDP/abs/html/here-docs.html - Example 19-7. (Thx to Jamie giving this pointer)

My workaround is leaving parameter substitution intact and use a tmp file and a sudo mv.

l_log=/var/log/server/server.log
l_logrotateconf=/etc/logrotate.d/server
tmp=/tmp/$$.eof
cat << EOF > $tmp
$l_log {
   rotate 12
   monthly
   compress
   missingok
   notifempty
}
EOF
sudo mv $tmp $logrotateconf