# CLI toolkit for shell command utilities
This module contains modules to implement CLI scripts by wrapping
python argparse.ArgumentParser to user friendly utility classes.
## Create a script class
Main class to use is the Script class. It will get it's name from
sys.argv[0].
Example:
```python
from cli_toolkit.script import Script
if __name__ == '__main__':
script = Script()
script.add_argument('files', nargs='*', help='Files to process')
args = script.parse_args()
for filename in args.files:
script.debug('PROCESSING', filename)
script.message(filename)
```
Running the example:
```
> python test.py foo bar
foo
bar
```
This is pretty straightforward ArgumentParser, except it
* sets SIGINT handler
* adds --debug and --quiet flags
* adds `debug` and `message` functions which honor the debug and quiet flags
## Using script with subcommands
More useful is using a script with subcommands. The subcommands require
at least `name` class variable and should have `usage`, `description` and
`epilog`.
You also should implement `run` method and call script.run() to run correct
subcommand. Arguments for subcommand parser are registered with method
`register_parser_arguments`.
```python
from cli_toolkit.script import Script
from cli_toolkit.command import Command
class ListCommand(Command):
name = 'list'
usage = 'List files'
description = 'Lists files specified on command line'
def register_parser_arguments(self, parser):
parser.add_argument('files', nargs='*', help='Files to process')
def run(self, args):
for filename in args.files:
self.debug('PROCESSING', filename)
self.message(filename)
if __name__ == '__main__':
script = Script()
script.add_subcommand(ListCommand(script))
script.run()
```
Running the example:
```bash
> python test.py list foo bar
foo
bar
```
## Using nested subcommands
The subcommands can be nested. You need to pass the parser in paren't
register_parser_subcommand to add_subcommand.
```python
from cli_toolkit.script import Script
from cli_toolkit.command import Command
class FilesCommand(Command):
name = 'demo'
usage = 'Run nested demo subcommands'
def register_parser_arguments(self, parser):
"""
Register 'list' command under demo subcommand
"""
self.add_subcommand(ListCommand(self), parser)
return parser
class ListCommand(Command):
name = 'list'
usage = 'List files'
description = 'Lists files specified on command line'
def register_parser_arguments(self, parser):
"""
Register 'list' command arguments
"""
parser.add_argument('files', nargs='*', help='Files to process')
return parser
def run(self, args):
if not args.files:
self.exit(1, 'No files provided')
for filename in args.files:
self.debug('PROCESSING', filename)
self.message(filename)
if __name__ == '__main__':
script = Script()
script.add_subcommand(FilesCommand(script))
script.run()
```
Running the example:
```bash
> python test.py demo list foo bar
foo
bar
```
