Bash脚本CAT命令使用脚本参数，而不是在cat'd文件中保留$ 1

Question

I am having a bit of an issue with a bash script when trying to cat a new file.

#!/bin/bash


#sudo vim /etc/init.d/glassfish

sudo cat > /etc/init.d/glassfish <<EOF

# Set path variable
GLASSFISH_HOME=/opt/glassfish3

# Establish Commands
case "$1" in
start)
    ${GLASSFISH_HOME}/bin/asadmin start-domain domain1
    ;;
stop)
    ${GLASSFISH_HOME}/bin/asadmin stop-domain domain1
    ;;
restart)
    ${GLASSFISH_HOME}/bin/asadmin stop-domain domain1
    ${GLASSFISH_HOME}/bin/asadmin start-domain domain1
    ;;
*)
    echo "usage: $0 {start|stop|restart}"
    ;;
esac    
exit 0
EOF>

However, when I run this script it replaces the $1 and $0 with what I used to call the script that runs the command, so $1 becomes "" and $0 becomes testscript.sh

Is there any way to prevent this?

Answer 1

If the here document delimiter is entirely unquoted, the contents are treated as a double-quoted string. Quote at least one character of the delimiter (it's simplest to just quote the whole thing) to have the here document treated as a single-quoted string, preventing parameter expansion.

sudo tee /etc/init.d/glassfish > /dev/null <<'EOF'
...
EOF

Why did I use tee instead of cat ? The output redirection is not affected by sudo , since the file is opened by the shell before sudo even runs. If you need sudo because you don't otherwise have write permission to /etc/init.d/ , you need to run a command like tee that opens the file itself.