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1 `cmd2` is a tool for writing command-line interactive applications. It is based on the Python Standard Library's `cmd` module, and can be used anyplace `cmd` is used simply by importing `cmd2` instead.
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2
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3 `cmd2` provides the following features, in addition to those already existing in `cmd`:
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4
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5 - Searchable command history
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6 - Load commands from file, save to file, edit commands in file
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7 - Multi-line commands
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8 - Case-insensitive commands
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9 - Special-character shortcut commands (beyond cmd's "@" and "!")
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10 - Settable environment parameters
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11 - Parsing commands with flags
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12
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13 Instructions for implementing each feature follow.
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14
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15 - Searchable command history
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16
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17 All commands will automatically be tracked in the session's history, unless the command is listed in Cmd's excludeFromHistory attribute.
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18 The history is accessed through the `history`, `list`, and `run` commands
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19 (and their abbreviations: `hi`, `li`, `l`, `r`).
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20 If you wish to exclude some of your custom commands from the history, append their names
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21 to the list at Cmd.ExcludeFromHistory.
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22
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23 - Load commands from file, save to file, edit commands in file
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24
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25 Type `help load`, `help save`, `help edit` for details.
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26
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27 - Multi-line commands
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28
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29 Any command accepts multi-line input when its name is listed in `Cmd.multilineCommands`.
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30 The program will keep expecting input until a line ends with any of the characters
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31 in `Cmd.terminators` . The default terminators are `;` and `/n` (empty newline).
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32
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33 - Case-insensitive commands
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34
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35 All commands are case-insensitive, unless `Cmd.caseInsensitive` is set to `False`.
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36
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37 - Special-character shortcut commands (beyond cmd's "@" and "!")
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38
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39 To create a single-character shortcut for a command, update `Cmd.shortcuts`.
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40
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41 - Settable environment parameters
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42
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43 To allow a user to change an environment parameter during program execution,
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44 append the parameter's name to `Cmd.settable`.
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45
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46 - Parsing commands with flags
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47
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48 To allow a command to parse flags:
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49
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50 1. Create a flagset: `flags = flagReader.FlagSet([flagReader.Flag('option')])`
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51 2. Within the command's function, `(opts, arg) = flags.parse(arg)`
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52 3. `opts` is a dictionary whose keys are the flags given, and whose values
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53 are the arguments to those flags (if any).
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54
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55 - Catherine Devlin, catherinedevlin.blogspot.com
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56
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57 cmd2 can be installed with `easy_install cmd2`
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58
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59 Cheese Shop page: http://pypi.python.org/pypi/cmd2/0.1
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60
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61 Example cmd2 application (cmd2_example.py) ::
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62
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63 from cmd2 import Cmd, flagReader
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64
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65 class CmdLineApp(Cmd):
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66 multilineCommands = ['orate']
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67 Cmd.shortcuts.update({'&': 'speak'})
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68 maxrepeats = 3
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69 Cmd.settable.append('maxrepeats')
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70 speakflags = flagReader.FlagSet([flagReader.Flag('piglatin'),
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71 flagReader.Flag('shout'),
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72 flagReader.Flag('repeat', nargs=1)
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73 ])
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74 def do_speak(self, arg):
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75 """Repeats what you tell me to.
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76
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77 args: --piglatin, -p: translate to Pig Latin
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78 --shout, -s: emulate internet newbie
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79 --repeat (nTimes), -r: be redundant"""
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80 (options, arg) = self.speakflags.parse(arg)
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81
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82 if options.has_key('piglatin'):
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83 arg = '%s%say' % (arg[1:], arg[0])
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84 if options.has_key('shout'):
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85 arg = arg.upper()
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86 repetitions = options.get('repeat')
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87 repetitions = int(repetitions[0]) if repetitions else 1
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88 for i in range(min(repetitions, self.maxrepeats)):
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89 self.stdout.write(arg)
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90 self.stdout.write('\n')
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91 # self.stdout.write is better than "print", because Cmd can be
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92 # initialized with a non-standard output destination
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93 do_say = do_speak # now "say" is a synonym for "speak"
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94 do_orate = do_speak # another synonym, but this one takes multi-line input
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95
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96 app = CmdLineApp()
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97 app.cmdloop()
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98
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99 Sample session using the above code ::
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100
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101 c:\cmd2>python cmd2_example.py
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102 (Cmd) speak softly
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103 softly
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104 (Cmd) speak --piglatin softly
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105 oftlysay
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106 (Cmd) speak -psr 2 softly
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107 OFTLYSAY
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108 OFTLYSAY
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109 (Cmd) speak --repeat 1000000 softly
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110 softly
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111 softly
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112 softly
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113 (Cmd) show maxrepeats
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114 maxrepeats: 3
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115 (Cmd) set maxrepeats 5
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116 maxrepeats - was: 3
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117 now: 5
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118 (Cmd) speak --repeat 1000000 softly
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119 softly
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120 softly
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121 softly
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122 softly
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123 softly
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124 (Cmd) orate blah blah
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125 > blah
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126 > and furthermore
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127 > blah
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128 >
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129 blah blah blah and furthermore blah
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130 (Cmd) &greetings
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131 greetings
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132 (Cmd) history
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133 -------------------------[1]
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134 speak softly
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135 -------------------------[2]
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136 speak --piglatin softly
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137 -------------------------[3]
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138 speak -psr 2 softly
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139 -------------------------[4]
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140 speak --repeat 1000000 softly
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141 -------------------------[5]
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142 show maxrepeats
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143 -------------------------[6]
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144 set maxrepeats 5
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145 -------------------------[7]
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146 speak --repeat 1000000 softly
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147 -------------------------[8]
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148 orate blah blah
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149 blah
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150 and furthermore
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151 blah
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152
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153 -------------------------[9]
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154 &greetings
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155 (Cmd) run
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156 orate blah blah
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157 blah
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158 and furthermore
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159 blah
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160
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161 blah blah blah and furthermore blah
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162 (Cmd) run 3
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163 speak -psr 2 softly
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164 OFTLYSAY
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165 OFTLYSAY
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166 (Cmd) history maxrepeats
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167 -------------------------[5]
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168 set maxrepeats
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169 -------------------------[6]
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170 set maxrepeats 5
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171 (Cmd)
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