vbl

Module: sys

Essential system functions

API


USAGE

source sys [list of functions to export]

By default, all functions are exported, so they can be used in sub-shells. It is also possible to specify which functions should be exported when a module is loaded by defining them as a list in the 'source' command or in the __sys_exported variable.

example:

#!/bin/bash

start() {
    source <(curl -sSLf http://vbl.vorakl.com/stable/sys) sys_cmd
}

start

__sys_version

This readonly variable contains a current module's version.


__sys_exported

This variable contains a list (separated by a space symbol) of functions that will be exported. It can be altered in the __sys_init__ function.


__sys_init__

This function has to be defined before the module is imported. It can be used for setting up default values for any function's variables.

example:

#!/bin/bash

__sys_init__() {
    __sys_exported="sys_cmd"
}

start() {
    source <(curl -sSLf http://vbl.vorakl.com/stable/sys)
}

start

sys_cmd

A wrapper for the builtin 'command' for minimizing a risk of reloading It works together with 'unset builtin' in the __sys_conf__ and the whole idea will work out only if Bash is run with the '--posix' option which doesn't allow to reload 'unset' builtin function. Anyway, you decide how deep is your paranoia ;) It's intended to be used for running builtin commands or standard tools. First, it checks in builtins. Then, it tries to find an external command.

usage:

sys_cmd arg [..]

parameters:

All parameters of the 'cmd' command. For instance:

  • -p, search in standard paths only
  • -v, check if a command exists

example:

#!/bin/bash

start() {
    source <(curl -sSLf http://vbl.vorakl.com/stable/sys)

    sys_cmd echo "Hello World"
    sys_cmd -v cp
    sys_cmd -p df -h
}

start