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bashsudoheredoc

Generate script in bash and save it to location requiring sudo

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?

Solution

  • 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.