Bash脚本从文件中读取并执行命令

Question

I want a bash script that reads the java arguments from a file and executes java with them

jvm_arguments=$(cat jvm-args)
exec java $jvm_arguments

The problem is that it does not work very well with this jvm-args file:

-Xms128m -Xmx512m -Dhostname=$(hostname)

The command hostname is not executed and replaced.

How can I get the hostname command executed? so that I get:

exec java -Xms128m -Xmx512m -Dhostname=MyMachine

Thanks.

Answer 1

Use eval to evaluate your runtime variables. Like this (not tested):

jvm_arguments=$(cat jvm-args)
eval java $jvm_arguments

Answer 2

Store the whole command in file, for example, run.sh

exec java -Xms128m -Xmx512m -Dhostname=$(hostname) ...

If you want current bash process to be terminated, call with . run.sh . run.sh