CODEWITHSUNDEEP
linuxbashtanuki
Happyblue
Happyblue

Reputation: 141

How can a Linux program - run by Tanuki wrapper - be made to 'see' aliases setup in .bash_profile?

How can I make a Java program running on Linux using Tanuki Wrapper (https://wrapper.tanukisoftware.com/) 'see' shell aliases?

The Java application is started by a 'Tanuki wrapper' script. The script is in turn started by nohup like this:

nohup ./start.sh &

Let's say I define an alias such as this in .bash_profile:

alias ls='ls -al'

When the Java application executes an operating system program or command such as ls, I expect ls -al to be executed. However, ls is executed -- the alias simply is not seen by the program. I understand aliases in Linux are typically not available in non-interactive shells (such as scripts or commands run by nohup).

So I tried modifications to force a login shell 'inside' the nohup command. But nothing works! The application doesn't see the aliases:

nohup bash -l -c "./start.sh" &

nohup bash -l -c "source .bash_profile; ./start.sh" &

I suspect the problem is Tanuki Wrapper. From what I understand, Tanuki Wrapper runs programs in a controlled environment that typically does not inherit the shell's interactive features or customizations.

How can I compel Tanuki wrapper to pickup settings from an interactive shell?

Upvotes: 0

Views: 39

Answers (1)

that other guy
that other guy

Reputation: 123470

You can't. Shell aliases don't hook into anything in the system in any way. It's simply the shell doing a search&replace on your input before interpreting it. Java programs don't do that so are unaffected by aliases.

Instead, you can create a wrapper script and add it to your PATH. This lets any program find and invoke the script instead of the backing command:

$ cat bin/ls
#!/bin/bash
/bin/ls -la "$@"

$ chmod +x bin/ls
(no output)

$ cat Test.java
class Test {
        public static void main(String[] args) throws Exception {
          new ProcessBuilder("ls").redirectOutput(ProcessBuilder.Redirect.INHERIT).start();
        }
}

If you don't change PATH, it uses the standard system ls:

$ java Test.java
bin  Test.java

If you do change it, the script is found first:

$ export PATH="$PWD/bin:$PATH"
$ java Test.java
total 16
drwxr-x---  3 user group 4096 Sep 19 18:26 .
drwxr-xr-x 45 user group 4096 Sep 19 18:26 ..
drwxr-x---  2 user group 4096 Sep 19 18:26 bin
-rw-r-----  1 user group  169 Sep 19 18:23 Test.java

Upvotes: 1

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