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1 =====
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2 Title
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3 =====
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4
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5 Web 2.0
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6 =======
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7
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8 .. image:: web-2-0-logos.gif
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9 :height: 300px
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10
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11 But first...
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12 ============
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13
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14 .. image:: sargon.jpg
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15 :height: 300px
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16
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17 Sargon the Great
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18 Founder of Akkadian Empire
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19
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20 .. twenty-third century BC
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21
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22 In between
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23 ==========
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24
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25 .. image:: apple.jpg
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26 :height: 300px
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27
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28 Command-Line Interface
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29 Unlike the Akkadian Empire,
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30 the CLI will never die.
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31
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32 Defining
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33 ========
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34
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35 - "Line-oriented command interpreter"
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36 - "Command-line interface"
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37 - "Shell"
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38
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39 * Accepts free text input at prompt
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40 * Outputs lines of text
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41 * Persistent CLI environment
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42
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43 Examples
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44 ========
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45
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46 * Bash, Korn, zsh
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47 * Python shell
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48 * screen
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49 * Zork
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50 * SQL clients: psql, SQL*\Plus, mysql...
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51 * ed
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52
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53 .. ``ed`` proves that CLI is sometimes the wrong answer.
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54
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55 != Command Line Utilities
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56 =========================
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57
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58 * Accept arguments at invocation
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59 * execution
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60 * terminate
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61
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62 Examples
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63 --------
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64 * ls
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65 * grep
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66 * ping
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67
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68 Use ``sys.argv``, ``optparse``
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69
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70 != "Text User Interfaces", "Consoles"
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71 =====================================
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72
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73 * Use entire (session) screen
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74 * I/O is *not* line-by-line
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75
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76 .. image:: urwid.png
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77 :height: 300px
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78
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79 Use ``curses``, ``urwid``
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80
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81 Tradeoff
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82 ========
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83
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84 .. image:: ease.png
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85 :height: 300px
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86
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87 pirate.py
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88 =========
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89
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90 ::
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91
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92 from cmd import Cmd
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93
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94 class Pirate(Cmd):
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95 pass
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96
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97 pirate = Pirate()
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98 pirate.cmdloop()
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99
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100 Nothing here... but history and help
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101
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102 .. ctrl-r for bash-style history
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103
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104 Fundamental prrrinciple
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105 =======================
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106
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107 .. class: huge
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108
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109 ``foo a b c`` ->
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110
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111 ``self.do_foo('a b c')``
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112
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113 ``do_``-methods: pirate2.py
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114 ===========================
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115
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116 ::
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117
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118 class Pirate(Cmd):
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119 gold = 10
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120 def do_loot(self, arg):
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121 'Seize booty frrrom a passing ship.'
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122 self.gold += 1
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123 print('Now we gots {0} doubloons'.format(self.gold))
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124 def do_drink(self, arg):
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125 'Drown your sorrrows in rrrum.'
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126 self.gold -= 1
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127 print('Now we gots {0} doubloons'.format(self.gold))
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128
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129 .. do_methods; more help
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130
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131 Hooks
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132 =====
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133
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134 .. image:: hook.jpeg
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135 :height: 300px
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136
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137 Hooks: pirate3.py
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138 =================
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139
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140 ::
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141
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142 class Pirate(Cmd):
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143 gold = 3
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144 def do_loot(self, arg):
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145 'Drown your sorrrows in rrrum.'
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146 self.gold += 1
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147 def do_drink(self, arg):
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148 'Drown your sorrrows in rrrum.'
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149 self.gold -= 1
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150 def postcmd(self, stop, line):
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151 print('Now we gots {0} doubloons'.format(self.gold))
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152
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153 Arguments: pirate4.py
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154 =====================
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155
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156 ::
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157
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158 def do_drink(self, arg):
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159 '''Drown your sorrrows in rrrum.
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160
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161 drink [n] - drink [n] barrel[s] o' rum.'''
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162 try:
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163 self.gold -= int(arg)
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164 except:
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165 if arg:
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166 print('''What's "{0}"? I'll take rrrum.'''.format(arg))
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167 self.gold -= 1
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168
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169 quitting: pirate5.py
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170 ====================
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171
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172 ::
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173
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174 def postcmd(self, stop, line):
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175 print('Now we gots {0} doubloons'.format(self.gold))
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176 if self.gold < 0:
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177 print("Off to debtorrr's prrrison. Game overrr.")
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178 return True
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179 return stop
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180 def do_quit(self, arg):
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181 print("Quiterrr!")
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182 return True
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183
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184 prompts and defaults: pirate6.py
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185 ================================
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186
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187 ::
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188
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189 prompt = 'arrr> '
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190 def default(self, line):
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191 print('What mean ye by "{0}"?'.format(line)) |
