321 lines
12 KiB
Python
Executable File
321 lines
12 KiB
Python
Executable File
#!/usr/bin/env python
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"""
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cheat.py -- cheat allows you to create and view interactive cheatsheets on the
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command-line. It was designed to help remind *nix system
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administrators of options for commands that they use frequently,
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but not frequently enough to remember.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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"""
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import os
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import sys
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import argparse
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import subprocess
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from textwrap import dedent
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DEFAULT_CHEAT_DIR = (os.environ.get('DEFAULT_CHEAT_DIR') or
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os.path.join(os.path.expanduser('~'), '.cheat'))
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USE_PYGMENTS = False
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# NOTE remove this check if it is confirmed to work on windows
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if os.name == 'posix' and 'CHEATCOLORS' in os.environ:
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try:
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from pygments import highlight
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from pygments.util import ClassNotFound
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from pygments.lexers import get_lexer_for_filename, TextLexer
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from pygments.formatters import TerminalFormatter
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USE_PYGMENTS = True
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except ImportError:
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pass
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def pretty_print(filename):
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"""Applies syntax highlighting to a cheatsheet and writes it to stdout"""
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try:
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if os.path.splitext(filename)[1]:
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lexer = get_lexer_for_filename(filename)
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else:
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# shell is a sensible default when there is no extension
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lexer = get_lexer_for_filename(filename + '.sh')
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except ClassNotFound:
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lexer = TextLexer()
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with open(filename) as istream:
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code = istream.read()
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fmt = TerminalFormatter()
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highlight(code, lexer, fmt, sys.stdout)
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class CheatSheets(object):
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"""Cheatsheets database class."""
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dirs = None
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sheets = None
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def __init__(self):
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self.dirs = self.__cheat_directories()
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# verify that we have at least one cheat directory
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if not self.dirs:
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error_msg = ('The {default} dir does not exist'
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' or the CHEATPATH var is not set.')
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print >> sys.stderr, error_msg.format(default=DEFAULT_CHEAT_DIR)
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exit(1)
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self.sheets = self.__cheat_files()
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def __cheat_directories(self):
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"""Assembles a list of directories containing cheatsheets."""
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default_directories = [DEFAULT_CHEAT_DIR]
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try:
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import cheatsheets
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default_directories.append(cheatsheets.cheat_dir)
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except ImportError:
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pass
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default = [default_dir for default_dir in default_directories
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if os.path.isdir(default_dir)]
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if 'CHEATPATH' in os.environ and os.environ['CHEATPATH']:
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return [path for path in os.environ['CHEATPATH'].split(os.pathsep)
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if os.path.isdir(path)] + default
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else:
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return default
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def __cheat_files(self):
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"""
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Assembles a dictionary of cheatsheets found in the above directories.
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"""
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cheats = {}
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for cheat_dir in reversed(self.dirs):
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cheats.update(dict([(cheat, cheat_dir)
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for cheat in os.listdir(cheat_dir)
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if not cheat.startswith('.')
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and not cheat.startswith('__')]))
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return cheats
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def edit(self, cheat):
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"""Creates or edits a cheatsheet"""
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# Assert that the EDITOR environment variable is set and that at least
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# 3 arguments have been given
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if 'EDITOR' not in os.environ:
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print >> sys.stderr, ('In order to create/edit a cheatsheet you '
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'must set your EDITOR environment variable '
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'to your favorite editor\'s path.')
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exit(1)
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elif os.environ['EDITOR'] == "":
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print >> sys.stderr, ('Your EDITOR environment variable is set '
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'to nothing, in order to create/edit a '
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'cheatsheet your must set it to a valid '
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'editor\'s path.')
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exit(1)
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else:
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editor = os.environ['EDITOR'].split()
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# if the cheatsheet already exists, open it for editing
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try:
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if cheat in self.sheets:
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sheet_path = os.path.join(self.sheets[cheat], cheat)
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if os.access(sheet_path, os.W_OK):
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subprocess.call(editor + [sheet_path])
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else:
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print >> sys.stderr, ("Sheet '%s' [%s] is not editable."
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% (cheat, sheet_path))
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print ('Do you want to '
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'copy it to your user cheatsheets directory [%s] '
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'before editing?\nKeep in mind that your sheet '
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'will always be used before system-wide one.'
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% DEFAULT_CHEAT_DIR)
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awn = raw_input('[y/n] ')
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if awn != 'y':
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print ('Ok, if you want to edit system-wide sheet, '
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'please try `cheat -e <cheatsheet>` '
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'again with sudo.')
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exit(1)
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import shutil
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# attempt to copy the cheatsheet to DEFAULT_CHEAT_DIR
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try:
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new_sheet = os.path.join(DEFAULT_CHEAT_DIR, cheat)
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shutil.copy(sheet_path, new_sheet)
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subprocess.call(editor + [new_sheet])
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# fail gracefully if the cheatsheet cannot be copied. This
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# can happen if DEFAULT_CHEAT_DIR does not exist
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except IOError:
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print ('Could not copy cheatsheet for editing.')
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exit(1)
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# otherwise, create it
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else:
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import cheatsheets as cs
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# Attempt to write the new cheatsheet to the user's ~/.cheat
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# dir if it exists. If it does not exist, attempt to create it.
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if os.access(DEFAULT_CHEAT_DIR, os.W_OK) or os.makedirs(DEFAULT_CHEAT_DIR):
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subprocess.call(editor
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+ [os.path.join(DEFAULT_CHEAT_DIR, cheat)])
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# If the directory cannot be created, write to the python
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# package directory, though that will likely require the use
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# of sudo
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else:
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if os.access(sheet_path, os.W_OK):
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subprocess.call(editor
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+ [os.path.join(cs.cheat_dir, cheat)])
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else:
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error_msg = ("Couldn't create '%s' cheatsheet.\n"
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"Please retry usig sudo." % cheat)
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print >> sys.stderr, error_msg
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exit(1)
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except OSError as errno:
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print >> sys.stderr, ("Could not launch `%s` as your editor : %s"
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% (editor[0], errno.strerror))
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exit(1)
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def list(self):
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"""Lists the cheatsheets that are currently available"""
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max_command = max([len(x) for x in self.sheets.keys()]) + 3
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return ('\n'.join(sorted(['%s [%s]' % (key.ljust(max_command), value)
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for key, value in self.sheets.items()])))
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def __parse_cheat_command_block(self, cheat):
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"""Parse text blocks inside specified sheet file"""
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block = ""
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path = os.path.join(self.sheets[cheat], cheat)
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with open(path) as cheat_fp:
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for line in cheat_fp.readlines():
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if line == '\n':
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if block:
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yield block
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block = ""
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else:
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block += line
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if block:
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yield block
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def search(self, term):
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"""Search for a term in sheetcheats"""
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for cheat in self.sheets.keys():
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output = ''
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for block in self.__parse_cheat_command_block(cheat):
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if term in block:
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if not output:
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output = cheat + ":\n"
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output += ''.join([" " + line + '\n' for line
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in block.split('\n')])
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if output:
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sys.stdout.write(output);
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# Custom action for argparse
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class ListDirectories(argparse.Action):
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"""List cheat directories and exit"""
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def __call__(self, parser, namespace, values, option_string=None):
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print("\n".join(sheets.dirs))
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parser.exit()
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class ListCheatsheets(argparse.Action):
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"""List cheatsheets and exit"""
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def __call__(self, parser, namespace, values, option_string=None):
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print(sheets.list());
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parser.exit()
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class EditSheet(argparse.Action):
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"""If the user wants to edit a cheatsheet"""
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def __call__(self, parser, namespace, values, option_string=None):
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sheets.edit(values[0])
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parser.exit()
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class SearchSheet(argparse.Action):
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"""If the user wants to search a term inside all cheatsheets"""
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def __call__(self, parser, namespace, values, option_string=None):
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sheets.search(values[0])
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parser.exit()
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def main():
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"""Main execution function"""
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global sheets
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sheets = CheatSheets()
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desc = dedent('''
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cheat allows you to create and view interactive cheatsheets on the
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command-line. It was designed to help remind *nix system
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administrators of options for commands that they use frequently,
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but not frequently enough to remember.''').strip()
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epi = dedent('''
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Examples:
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To look up 'tar':
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cheat tar
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To create or edit the cheatsheet for 'foo':
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cheat -e foo
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To list the directories on the CHEATPATH
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cheat -d
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To list the available cheatsheets:
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cheat -l
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''').strip()
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parser = argparse.ArgumentParser(prog='cheat',
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description=desc, epilog=epi,
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formatter_class=argparse.
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RawDescriptionHelpFormatter)
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parser_group = parser.add_mutually_exclusive_group()
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parser_group.add_argument('sheet', metavar='cheatsheet',
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action='store', type=str, nargs='?',
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help='Look at <cheatseet>')
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parser_group.add_argument('-e', '--edit', metavar='cheatsheet',
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action=EditSheet, type=str, nargs=1,
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help='Edit <cheatsheet>')
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parser_group.add_argument('-s', '--search', metavar='term',
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action=SearchSheet, type=str, nargs=1,
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help='Search <term> inside all cheatsheets')
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parser_group.add_argument('-l', '--list',
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action=ListCheatsheets, nargs=0,
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help='List all available cheatsheets')
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parser_group.add_argument('-d', '--cheat-directories',
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action=ListDirectories, nargs=0,
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help='List all current cheat dirs')
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args = parser.parse_args()
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sheet = args.sheet
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# Print the cheatsheet if it exists
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if not sheet or sheet in ['help', 'cheat']:
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parser.print_help()
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elif sheet in sheets.sheets:
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filename = os.path.join(sheets.sheets[sheet], sheet)
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if USE_PYGMENTS:
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pretty_print(filename)
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else:
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with open(filename) as istream:
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for line in istream:
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sys.stdout.write(line)
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# if it does not, say so
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else:
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print >> sys.stderr, ('No cheatsheet found for %s.' % sheet)
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exit(1)
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exit()
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if __name__ == '__main__':
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main()
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