Question

I am trying to write a bash script that simply compiles a java file then runs it

#!/bin/bash
read name
javac $name
$name | sed -r "s/.java//" | java

but instead of running the java file, it opens java.

Usage: java [-options] class [args...]
           (to execute a class)
   or  java [-options] -jar jarfile [args...]
           (to execute a jar file)

       blah blah blah

Answer 1

Try substituting this:

#!/bin/bash
read name
javac $name
name=$(echo $name|sed -r "s/.java//")
java $name 

Or, even better: just enter the main class without “.java”:

#!/bin/bash
read name
javac $name.java
java $name 

The point is, you need to pass an argument to the “java” command. You can’t just use a pipe from stdout.