shell

Execute the shell command and return the output.

Function Arguments

Name	Type	Description
command	str	The shell command.
key	str	(optional; default: 'shell_raw') The key of the result.
split_line	bool	(optional; default: False) True to split lines to multiple results.

Description

This function executes the specific shell command and takes the standard output of that command as the probed results if the return code is zero.

The output of a probe function is always in dictionary type. The output of this function will contain only one entry, whose key is specified by the argument key and the value is the standard output of the command.

Examples

Let’s assume that the output of the command ls is:

aaa
bbb
ccc

Then the probe statement

{
  "eval": "shell:ls"
}

will have the corresponding probed result

[
  {
    "shell_raw": "aaa\nbbb\nccc"
  }
]

Another example is that the probe statement

{
  "eval": {
    "shell": {
      "command": "ls",
      "split_line": true,   # Treat each line as different probe results.
      "key": "my_key_name"  # Use "my_key_name" as the key in the output
                            # dictionary
    }
  }
}

will have the corresponding probed results

[
  {
    "my_key_name": "aaa"
  },
  {
    "my_key_name": "bbb"
  },
  {
    "my_key_name": "ccc"
  }
]

The command can be even more complex like

{
  "eval": "shell:ls | grep aaa"
}

In above case, the probed result will be empty if the output of ls command doesn’t contain aaa because grep aaa will have a non-zero return code when it cannot find aaa from its standard input.