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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<HTML>
<!--Time-stamp: <2006-04-22 03:52:58 poser> -->
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=utf-8">
<META NAME="Author" CONTENT="Bill Poser">
<TITLE>Redet Reference Manual: Builtin Character Classes</TITLE>
</HEAD>
<BODY TEXT="#000000" BGCOLOR="#FFE2C0" VLINK="#0000EE" LINK="#AA0066" ALINK="#FF0000">
<H2><a name="charclass">Builtin Character Classes</a></H2>
<P>
Most regular expression matchers provide a number of built-in character classes, most commonly
the classes defined by the POSIX standard. Some provide more than one set: Java, for example, provides
the POSIX classes, the Unicode classes, and a set of classes resembling the POSIX classes but differing
from them in some respects.
</p>
<P>
The Unicode classes are based on the Unicode General Character Properties. A list of these
categories and the abbreviations used for them is provided on the Help menu.
The classification of every character can be found in the file
<a href="http://www.unicode.org/Public/UNIDATA/UnicodeData.txt">UnicodeData.txt</a>
distributed by the Unicode Consortium.
</p>
<P>
The POSIX classes are defined very concretely for the ASCII character set. Outside of ASCII
they are defined only by certain general principles. Implementors have some discretion in how
they classify characters. Here are ASCII charts color-coded to show the basic POSIX classes.
</p>
<br>
<h3>Binary</h3>
<DIV align="center">
<table border="2" cellpadding="3" width="600">
<TR>
<TD>
00000000</TD><TD align="center" bgcolor="yellow">nul</TD><TD>
00000001</TD><TD align="center" bgcolor="yellow">soh</TD><TD>
00000010</TD><TD align="center" bgcolor="yellow">stx</TD><TD>
00000011</TD><TD align="center" bgcolor="yellow">etx</TD><TD>
00000100</TD><TD align="center" bgcolor="yellow">eot</TD><TD>
00000101</TD><TD align="center" bgcolor="yellow">enq</TD><TD>
00000110</TD><TD align="center" bgcolor="yellow">ack</TD><TD>
00000111</TD><TD align="center" bgcolor="yellow">bel</TD>
</TR>
<TR>
<TD>
00001000</TD><TD align="center" bgcolor="yellow">bs</TD><TD>
00001001</TD><TD align="center" bgcolor="yellow">tab</TD><TD>
00001010</TD><TD align="center" bgcolor="yellow">nl</TD><TD>
00001011</TD><TD align="center" bgcolor="yellow">vt</TD><TD>
00001100</TD><TD align="center" bgcolor="yellow">ff</TD><TD>
00001101</TD><TD align="center" bgcolor="yellow">cr</TD><TD>
00001110</TD><TD align="center" bgcolor="yellow">so</TD><TD>
00001111</TD><TD align="center" bgcolor="yellow">si</TD>
</TR>
<TR>
<TD>
00010000</TD><TD align="center" bgcolor="yellow">dle</TD><TD>
00010001</TD><TD align="center" bgcolor="yellow">dc1</TD><TD>
00010010</TD><TD align="center" bgcolor="yellow">dc2</TD><TD>
00010011</TD><TD align="center" bgcolor="yellow">dc3</TD><TD>
00010100</TD><TD align="center" bgcolor="yellow">dc4</TD><TD>
00010101</TD><TD align="center" bgcolor="yellow">nak</TD><TD>
00010110</TD><TD align="center" bgcolor="yellow">syn</TD><TD>
00010111</TD><TD align="center" bgcolor="yellow">etb</TD>
</TR>
<TR>
<TD>
00011000</TD><TD align="center" bgcolor="yellow">can</TD><TD>
00011001</TD><TD align="center" bgcolor="yellow">em</TD><TD>
00011010</TD><TD align="center" bgcolor="yellow">sub</TD><TD>
00011011</TD><TD align="center" bgcolor="yellow">esc</TD><TD>
00011100</TD><TD align="center" bgcolor="yellow">fs</TD><TD>
00011101</TD><TD align="center" bgcolor="yellow">gs</TD><TD>
00011110</TD><TD align="center" bgcolor="yellow">rs</TD><TD>
00011111</TD><TD align="center" bgcolor="yellow">us</TD>
</TR>
<TR>
<TD>
00100000</TD><TD align="center" bgcolor="white">sp</TD><TD>
00100001</TD><TD align="center" bgcolor="lightblue">!</TD><TD>
00100010</TD><TD align="center" bgcolor="lightblue">"</TD><TD>
00100011</TD><TD align="center" bgcolor="lightblue">#</TD><TD>
00100100</TD><TD align="center" bgcolor="lightblue">$</TD><TD>
00100101</TD><TD align="center" bgcolor="lightblue">%</TD><TD>
00100110</TD><TD align="center" bgcolor="lightblue">&</TD><TD>
00100111</TD><TD align="center" bgcolor="lightblue">'</TD>
</TR>
<TR>
<TD>
00101000</TD><TD align="center" bgcolor="lightblue">(</TD><TD>
00101001</TD><TD align="center" bgcolor="lightblue">)</TD><TD>
00101010</TD><TD align="center" bgcolor="lightblue">*</TD><TD>
00101011</TD><TD align="center" bgcolor="lightblue">+</TD><TD>
00101100</TD><TD align="center" bgcolor="lightblue">,</TD><TD>
00101101</TD><TD align="center" bgcolor="lightblue">-</TD><TD>
00101110</TD><TD align="center" bgcolor="lightblue">.</TD><TD>
00101111</TD><TD align="center" bgcolor="lightblue">/</TD>
</TR>
<TR>
<TD>
00110000</TD><TD align="center" bgcolor="navajowhite">0</TD><TD>
00110001</TD><TD align="center" bgcolor="navajowhite">1</TD><TD>
00110010</TD><TD align="center" bgcolor="navajowhite">2</TD><TD>
00110011</TD><TD align="center" bgcolor="navajowhite">3</TD><TD>
00110100</TD><TD align="center" bgcolor="navajowhite">4</TD><TD>
00110101</TD><TD align="center" bgcolor="navajowhite">5</TD><TD>
00110110</TD><TD align="center" bgcolor="navajowhite">6</TD><TD>
00110111</TD><TD align="center" bgcolor="navajowhite">7</TD>
</TR>
<TR>
<TD>
00111000</TD><TD align="center" bgcolor="navajowhite">8</TD><TD>
00111001</TD><TD align="center" bgcolor="navajowhite">9</TD><TD>
00111010</TD><TD align="center" bgcolor="lightblue">:</TD><TD>
00111011</TD><TD align="center" bgcolor="lightblue">;</TD><TD>
00111100</TD><TD align="center" bgcolor="lightblue"><</TD><TD>
00111101</TD><TD align="center" bgcolor="lightblue">=</TD><TD>
00111110</TD><TD align="center" bgcolor="lightblue">></TD><TD>
00111111</TD><TD align="center" bgcolor="lightblue">?</TD>
</TR>
<TR>
<TD>
01000000</TD><TD align="center" bgcolor="lightblue">@</TD><TD>
01000001</TD><TD align="center" bgcolor="lightgreen">A</TD><TD>
01000010</TD><TD align="center" bgcolor="lightgreen">B</TD><TD>
01000011</TD><TD align="center" bgcolor="lightgreen">C</TD><TD>
01000100</TD><TD align="center" bgcolor="lightgreen">D</TD><TD>
01000101</TD><TD align="center" bgcolor="lightgreen">E</TD><TD>
01000110</TD><TD align="center" bgcolor="lightgreen">F</TD><TD>
01000111</TD><TD align="center" bgcolor="lightgreen">G</TD>
</TR>
<TR>
<TD>
01001000</TD><TD align="center" bgcolor="lightgreen">H</TD><TD>
01001001</TD><TD align="center" bgcolor="lightgreen">I</TD><TD>
01001010</TD><TD align="center" bgcolor="lightgreen">J</TD><TD>
01001011</TD><TD align="center" bgcolor="lightgreen">K</TD><TD>
01001100</TD><TD align="center" bgcolor="lightgreen">L</TD><TD>
01001101</TD><TD align="center" bgcolor="lightgreen">M</TD><TD>
01001110</TD><TD align="center" bgcolor="lightgreen">N</TD><TD>
01001111</TD><TD align="center" bgcolor="lightgreen">O</TD>
</TR>
<TR>
<TD>
01010000</TD><TD align="center" bgcolor="lightgreen">P</TD><TD>
01010001</TD><TD align="center" bgcolor="lightgreen">Q</TD><TD>
01010010</TD><TD align="center" bgcolor="lightgreen">R</TD><TD>
01010011</TD><TD align="center" bgcolor="lightgreen">S</TD><TD>
01010100</TD><TD align="center" bgcolor="lightgreen">T</TD><TD>
01010101</TD><TD align="center" bgcolor="lightgreen">U</TD><TD>
01010110</TD><TD align="center" bgcolor="lightgreen">V</TD><TD>
01010111</TD><TD align="center" bgcolor="lightgreen">W</TD>
</TR>
<TR><TD>
01011000</TD><TD align="center" bgcolor="lightgreen">X</TD><TD>
01011001</TD><TD align="center" bgcolor="lightgreen">Y</TD><TD>
01011010</TD><TD align="center" bgcolor="lightgreen">Z</TD><TD>
01011011</TD><TD align="center" bgcolor="lightblue">[</TD><TD>
01011100</TD><TD align="center" bgcolor="lightblue">\</TD><TD>
01011101</TD><TD align="center" bgcolor="lightblue">]</TD><TD>
01011110</TD><TD align="center" bgcolor="lightblue">^</TD><TD>
01011111</TD><TD align="center" bgcolor="lightblue">_</TD>
</TR>
<TR><TD>
01100000</TD><TD align="center" bgcolor="lightblue">`</TD><TD>
01100001</TD><TD align="center" bgcolor="coral">a</TD><TD>
01100010</TD><TD align="center" bgcolor="coral">b</TD><TD>
01100011</TD><TD align="center" bgcolor="coral">c</TD><TD>
01100100</TD><TD align="center" bgcolor="coral">d</TD><TD>
01100101</TD><TD align="center" bgcolor="coral">e</TD><TD>
01100110</TD><TD align="center" bgcolor="coral">f</TD><TD>
01100111</TD><TD align="center" bgcolor="coral">g</TD>
</TR>
<TR><TD>
01101000</TD><TD align="center" bgcolor="coral">h</TD><TD>
01101001</TD><TD align="center" bgcolor="coral">i</TD><TD>
01101010</TD><TD align="center" bgcolor="coral">j</TD><TD>
01101011</TD><TD align="center" bgcolor="coral">k</TD><TD>
01101100</TD><TD align="center" bgcolor="coral">l</TD><TD>
01101101</TD><TD align="center" bgcolor="coral">m</TD><TD>
01101110</TD><TD align="center" bgcolor="coral">n</TD><TD>
01101111</TD><TD align="center" bgcolor="coral">o</TD>
</TR>
<TR>
<TD>
01110000</TD><TD align="center" bgcolor="coral">p</TD><TD>
01110001</TD><TD align="center" bgcolor="coral">q</TD><TD>
01110010</TD><TD align="center" bgcolor="coral">r</TD><TD>
01110011</TD><TD align="center" bgcolor="coral">s</TD><TD>
01110100</TD><TD align="center" bgcolor="coral">t</TD><TD>
01110101</TD><TD align="center" bgcolor="coral">u</TD><TD>
01110110</TD><TD align="center" bgcolor="coral">v</TD><TD>
01110111</TD><TD align="center" bgcolor="coral">w</TD>
</TR>
<TR>
<TD>
01111000</TD><TD align="center" bgcolor="coral">x</TD><TD>
01111001</TD><TD align="center" bgcolor="coral">y</TD><TD>
01111010</TD><TD align="center" bgcolor="coral">z</TD><TD>
01111011</TD><TD align="center" bgcolor="lightblue">{</TD><TD>
01111100</TD><TD align="center" bgcolor="lightblue">|</TD><TD>
01111101</TD><TD align="center" bgcolor="lightblue">}</TD><TD>
01111110</TD><TD align="center" bgcolor="lightblue">~</TD><TD>
01111111</TD><TD align="center" bgcolor="yellow">del</TD>
</TR>
</TABLE>
</DIV>
<br>
<br>
<h3>Octal</h3>
<div align="center">
<table border="2" cellpadding="3" width="600">
<tbody><tr>
<td>000</td><td align="center" bgcolor="yellow">nul</td><td>001</td><td align="center" bgcolor="yellow">soh</td><td>002</td><td align="center" bgcolor="yellow">stx</td><td>003</td><td align="center" bgcolor="yellow">etx</td><td>004</td><td align="center" bgcolor="yellow">eot</td><td>005</td><td align="center" bgcolor="yellow">enq</td><td>006</td><td align="center" bgcolor="yellow">ack</td><td>007</td><td align="center" bgcolor="yellow">bel</td>
</tr>
<tr>
<td>010</td><td align="center" bgcolor="yellow">bs</td><td>011</td><td align="center" bgcolor="yellow">tab</td><td>012</td><td align="center" bgcolor="yellow">nl</td><td>013</td><td align="center" bgcolor="yellow">vt</td><td>014</td><td align="center" bgcolor="yellow">ff</td><td>015</td><td align="center" bgcolor="yellow">cr</td><td>016</td><td align="center" bgcolor="yellow">so</td><td>017</td><td align="center" bgcolor="yellow">si</td>
</tr>
<tr>
<td>020</td><td align="center" bgcolor="yellow">dle</td><td>021</td><td align="center" bgcolor="yellow">dc1</td><td>022</td><td align="center" bgcolor="yellow">dc2</td><td>023</td><td align="center" bgcolor="yellow">dc3</td><td>024</td><td align="center" bgcolor="yellow">dc4</td><td>025</td><td align="center" bgcolor="yellow">nak</td><td>026</td><td align="center" bgcolor="yellow">syn</td><td>027</td><td align="center" bgcolor="yellow">etb</td>
</tr>
<tr>
<td>030</td><td align="center" bgcolor="yellow">can</td><td>031</td><td align="center" bgcolor="yellow">em</td><td>032</td><td align="center" bgcolor="yellow">sub</td><td>033</td><td align="center" bgcolor="yellow">esc</td><td>034</td><td align="center" bgcolor="yellow">fs</td><td>035</td><td align="center" bgcolor="yellow">gs</td><td>036</td><td align="center" bgcolor="yellow">rs</td><td>037</td><td align="center" bgcolor="yellow">us</td>
</tr>
<tr>
<td>040</td><td align="center" bgcolor="white">sp</td><td>041</td><td align="center" bgcolor="lightblue">!</td><td>042</td><td align="center" bgcolor="lightblue">"</td><td>043</td><td align="center" bgcolor="lightblue">#</td><td>044</td><td align="center" bgcolor="lightblue">$</td><td>045</td><td align="center" bgcolor="lightblue">%</td><td>046</td><td align="center" bgcolor="lightblue">&</td><td>047</td><td align="center" bgcolor="lightblue">'</td>
</tr>
<tr>
<td>050</td><td align="center" bgcolor="lightblue">(</td><td>051</td><td align="center" bgcolor="lightblue">)</td><td>052</td><td align="center" bgcolor="lightblue">*</td><td>053</td><td align="center" bgcolor="lightblue">+</td><td>054</td><td align="center" bgcolor="lightblue">,</td><td>055</td><td align="center" bgcolor="lightblue">-</td><td>056</td><td align="center" bgcolor="lightblue">.</td><td>057</td><td align="center" bgcolor="lightblue">/</td>
</tr>
<tr>
<td>060</td><td align="center" bgcolor="navajowhite">0</td><td>061</td><td align="center" bgcolor="navajowhite">1</td><td>062</td><td align="center" bgcolor="navajowhite">2</td><td>063</td><td align="center" bgcolor="navajowhite">3</td><td>064</td><td align="center" bgcolor="navajowhite">4</td><td>065</td><td align="center" bgcolor="navajowhite">5</td><td>066</td><td align="center" bgcolor="navajowhite">6</td><td>067</td><td align="center" bgcolor="navajowhite">7</td>
</tr>
<tr>
<td>070</td><td align="center" bgcolor="navajowhite">8</td><td>071</td><td align="center" bgcolor="navajowhite">9</td><td>072</td><td align="center" bgcolor="lightblue">:</td><td>073</td><td align="center" bgcolor="lightblue">;</td><td>074</td><td align="center" bgcolor="lightblue"><</td><td>075</td><td align="center" bgcolor="lightblue">=</td><td>076</td><td align="center" bgcolor="lightblue">></td><td>077</td><td align="center" bgcolor="lightblue">?</td>
</tr>
<tr>
<td>100</td><td align="center" bgcolor="lightblue">@</td><td>101</td><td align="center" bgcolor="lightgreen">A</td><td>102</td><td align="center" bgcolor="lightgreen">B</td><td>103</td><td align="center" bgcolor="lightgreen">C</td><td>104</td><td align="center" bgcolor="lightgreen">D</td><td>105</td><td align="center" bgcolor="lightgreen">E</td><td>106</td><td align="center" bgcolor="lightgreen">F</td><td>107</td><td align="center" bgcolor="lightgreen">G</td>
</tr>
<tr>
<td>110</td><td align="center" bgcolor="lightgreen">H</td><td>111</td><td align="center" bgcolor="lightgreen">I</td><td>112</td><td align="center" bgcolor="lightgreen">J</td><td>113</td><td align="center" bgcolor="lightgreen">K</td><td>114</td><td align="center" bgcolor="lightgreen">L</td><td>115</td><td align="center" bgcolor="lightgreen">M</td><td>116</td><td align="center" bgcolor="lightgreen">N</td><td>117</td><td align="center" bgcolor="lightgreen">O</td>
</tr>
<tr>
<td>120</td><td align="center" bgcolor="lightgreen">P</td><td>121</td><td align="center" bgcolor="lightgreen">Q</td><td>122</td><td align="center" bgcolor="lightgreen">R</td><td>123</td><td align="center" bgcolor="lightgreen">S</td><td>124</td><td align="center" bgcolor="lightgreen">T</td><td>125</td><td align="center" bgcolor="lightgreen">U</td><td>126</td><td align="center" bgcolor="lightgreen">V</td><td>127</td><td align="center" bgcolor="lightgreen">W</td>
</tr>
<tr>
<td>130</td><td align="center" bgcolor="lightgreen">X</td><td>131</td><td align="center" bgcolor="lightgreen">Y</td><td>132</td><td align="center" bgcolor="lightgreen">Z</td><td>133</td><td align="center" bgcolor="lightblue">[</td><td>134</td><td align="center" bgcolor="lightblue">\</td><td>135</td><td align="center" bgcolor="lightblue">]</td><td>136</td><td align="center" bgcolor="lightblue">^</td><td>137</td><td align="center" bgcolor="lightblue">_</td>
</tr>
<tr>
<td>140</td><td align="center" bgcolor="lightblue">`</td><td>141</td><td align="center" bgcolor="coral">a</td><td>142</td><td align="center" bgcolor="coral">b</td><td>143</td><td align="center" bgcolor="coral">c</td><td>144</td><td align="center" bgcolor="coral">d</td><td>145</td><td align="center" bgcolor="coral">e</td><td>146</td><td align="center" bgcolor="coral">f</td><td>147</td><td align="center" bgcolor="coral">g</td>
</tr>
<tr>
<td>150</td><td align="center" bgcolor="coral">h</td><td>151</td><td align="center" bgcolor="coral">i</td><td>152</td><td align="center" bgcolor="coral">j</td><td>153</td><td align="center" bgcolor="coral">k</td><td>154</td><td align="center" bgcolor="coral">l</td><td>155</td><td align="center" bgcolor="coral">m</td><td>156</td><td align="center" bgcolor="coral">n</td><td>157</td><td align="center" bgcolor="coral">o</td>
</tr>
<tr>
<td>160</td><td align="center" bgcolor="coral">p</td><td>161</td><td align="center" bgcolor="coral">q</td><td>162</td><td align="center" bgcolor="coral">r</td><td>163</td><td align="center" bgcolor="coral">s</td><td>164</td><td align="center" bgcolor="coral">t</td><td>165</td><td align="center" bgcolor="coral">u</td><td>166</td><td align="center" bgcolor="coral">v</td><td>167</td><td align="center" bgcolor="coral">w</td>
</tr>
<tr>
<td>170</td><td align="center" bgcolor="coral">x</td><td>171</td><td align="center" bgcolor="coral">y</td><td>172</td><td align="center" bgcolor="coral">z</td><td>173</td><td align="center" bgcolor="lightblue">{</td><td>174 </td><td align="center" bgcolor="lightblue">|</td><td>175</td><td align="center" bgcolor="lightblue">}</td><td>176</td><td align="center" bgcolor="lightblue">~</td><td>177</td><td align="center" bgcolor="yellow">del</td>
</tr>
</tbody></table>
</div>
<br>
<br>
<h3>Decimal</h3>
<div align="center">
<table border="2" cellpadding="3" width="600">
<tbody><tr>
<td>00</td><td align="center" bgcolor="yellow">nul</td><td>01</td><td align="center" bgcolor="yellow">soh</td><td>02</td><td align="center" bgcolor="yellow">stx</td><td>03</td><td align="center" bgcolor="yellow">etx</td><td>04</td><td align="center" bgcolor="yellow">eot</td><td>05</td><td align="center" bgcolor="yellow">enq</td><td>06</td><td align="center" bgcolor="yellow">ack</td><td>07</td><td align="center" bgcolor="yellow">bel</td>
</tr>
<tr>
<td>08</td><td align="center" bgcolor="yellow">bs</td><td>09</td><td align="center" bgcolor="yellow">tab</td><td>10</td><td align="center" bgcolor="yellow">nl</td><td>11</td><td align="center" bgcolor="yellow">vt</td><td>12</td><td align="center" bgcolor="yellow">ff</td><td>13</td><td align="center" bgcolor="yellow">cr</td><td>14</td><td align="center" bgcolor="yellow">so</td><td>15</td><td align="center" bgcolor="yellow">si</td>
</tr>
<tr>
<td>16</td><td align="center" bgcolor="yellow">dle</td><td>17</td><td align="center" bgcolor="yellow">dc1</td><td>18</td><td align="center" bgcolor="yellow">dc2</td><td>19</td><td align="center" bgcolor="yellow">dc3</td><td>20</td><td align="center" bgcolor="yellow">dc4</td><td>21</td><td align="center" bgcolor="yellow">nak</td><td>22</td><td align="center" bgcolor="yellow">syn</td><td>23</td><td align="center" bgcolor="yellow">etb</td>
</tr>
<tr>
<td>24</td><td align="center" bgcolor="yellow">can</td><td>25</td><td align="center" bgcolor="yellow">em</td><td>26</td><td align="center" bgcolor="yellow">sub</td><td>27</td><td align="center" bgcolor="yellow">esc</td><td>28</td><td align="center" bgcolor="yellow">fs</td><td>29</td><td align="center" bgcolor="yellow">gs</td><td>30</td><td align="center" bgcolor="yellow">rs</td><td>31</td><td align="center" bgcolor="yellow">us</td>
</tr>
<tr>
<td>32</td><td align="center" bgcolor="white">sp</td><td>33</td><td align="center" bgcolor="lightblue">!</td><td>34</td><td align="center" bgcolor="lightblue">"</td><td>35</td><td align="center" bgcolor="lightblue">#</td><td>36</td><td align="center" bgcolor="lightblue">$</td><td>37</td><td align="center" bgcolor="lightblue">%</td><td>38</td><td align="center" bgcolor="lightblue">&</td><td>39</td><td align="center" bgcolor="lightblue">'</td>
</tr>
<tr>
<td>40</td><td align="center" bgcolor="lightblue">(</td><td>41</td><td align="center" bgcolor="lightblue">)</td><td>42</td><td align="center" bgcolor="lightblue">*</td><td>43</td><td align="center" bgcolor="lightblue">+</td><td>44</td><td align="center" bgcolor="lightblue">,</td><td>45</td><td align="center" bgcolor="lightblue">-</td><td>46</td><td align="center" bgcolor="lightblue">.</td><td>47</td><td align="center" bgcolor="lightblue">/</td>
</tr>
<tr>
<td>48</td><td align="center" bgcolor="navajowhite">0</td><td>49</td><td align="center" bgcolor="navajowhite">1</td><td>50</td><td align="center" bgcolor="navajowhite">2</td><td>51</td><td align="center" bgcolor="navajowhite">3</td><td>52</td><td align="center" bgcolor="navajowhite">4</td><td>53</td><td align="center" bgcolor="navajowhite">5</td><td>54</td><td align="center" bgcolor="navajowhite">6</td><td>55</td><td align="center" bgcolor="navajowhite">7</td>
</tr>
<tr>
<td>56</td><td align="center" bgcolor="navajowhite">8</td><td>57</td><td align="center" bgcolor="navajowhite">9</td><td>58</td><td align="center" bgcolor="lightblue">:</td><td>59</td><td align="center" bgcolor="lightblue">;</td><td>60</td><td align="center" bgcolor="lightblue"><</td><td>61</td><td align="center" bgcolor="lightblue">=</td><td>62</td><td align="center" bgcolor="lightblue">></td><td>63</td><td align="center" bgcolor="lightblue">?</td>
</tr>
<tr>
<td>64</td><td align="center" bgcolor="lightblue">@</td><td>65</td><td align="center" bgcolor="lightgreen">A</td><td>66</td><td align="center" bgcolor="lightgreen">B</td><td>67</td><td align="center" bgcolor="lightgreen">C</td><td>68</td><td align="center" bgcolor="lightgreen">D</td><td>69</td><td align="center" bgcolor="lightgreen">E</td><td>70</td><td align="center" bgcolor="lightgreen">F</td><td>71</td><td align="center" bgcolor="lightgreen">G</td>
</tr>
<tr>
<td>72</td><td align="center" bgcolor="lightgreen">H</td><td>73</td><td align="center" bgcolor="lightgreen">I</td><td>74</td><td align="center" bgcolor="lightgreen">J</td><td>75</td><td align="center" bgcolor="lightgreen">K</td><td>76</td><td align="center" bgcolor="lightgreen">L</td><td>77</td><td align="center" bgcolor="lightgreen">M</td><td>78</td><td align="center" bgcolor="lightgreen">N</td><td>79</td><td align="center" bgcolor="lightgreen">O</td>
</tr>
<tr>
<td>80</td><td align="center" bgcolor="lightgreen">P</td><td>81</td><td align="center" bgcolor="lightgreen">Q</td><td>82</td><td align="center" bgcolor="lightgreen">R</td><td>83</td><td align="center" bgcolor="lightgreen">S</td><td>84</td><td align="center" bgcolor="lightgreen">T</td><td>85</td><td align="center" bgcolor="lightgreen">U</td><td>86</td><td align="center" bgcolor="lightgreen">V</td><td>87</td><td align="center" bgcolor="lightgreen">W</td>
</tr>
<tr>
<td>88</td><td align="center" bgcolor="lightgreen">X</td><td>89</td><td align="center" bgcolor="lightgreen">Y</td><td>90</td><td align="center" bgcolor="lightgreen">Z</td><td>91</td><td align="center" bgcolor="lightblue">[</td><td>92</td><td align="center" bgcolor="lightblue">\</td><td>93</td><td align="center" bgcolor="lightblue">]</td><td>94</td><td align="center" bgcolor="lightblue">^</td><td>95</td><td align="center" bgcolor="lightblue">_</td>
</tr>
<tr>
<td>96</td><td align="center" bgcolor="lightblue">`</td><td>97</td><td align="center" bgcolor="coral">a</td><td>98</td><td align="center" bgcolor="coral">b</td><td>99</td><td align="center" bgcolor="coral">c</td><td>100</td><td align="center" bgcolor="coral">d</td><td>101</td><td align="center" bgcolor="coral">e</td><td>102</td><td align="center" bgcolor="coral">f</td><td>103</td><td align="center" bgcolor="coral">g</td>
</tr>
<tr>
<td>104</td><td align="center" bgcolor="coral">h</td><td>105</td><td align="center" bgcolor="coral">i</td><td>106</td><td align="center" bgcolor="coral">j</td><td>107</td><td align="center" bgcolor="coral">k</td><td>108</td><td align="center" bgcolor="coral">l</td><td>109</td><td align="center" bgcolor="coral">m</td><td>110</td><td align="center" bgcolor="coral">n</td><td>111</td><td align="center" bgcolor="coral">o</td>
</tr>
<tr>
<td>112</td><td align="center" bgcolor="coral">p</td><td>113</td><td align="center" bgcolor="coral">q</td><td>114</td><td align="center" bgcolor="coral">r</td><td>115</td><td align="center" bgcolor="coral">s</td><td>116</td><td align="center" bgcolor="coral">t</td><td>117</td><td align="center" bgcolor="coral">u</td><td>118</td><td align="center" bgcolor="coral">v</td><td>119</td><td align="center" bgcolor="coral">w</td>
</tr>
<tr>
<td>120</td><td align="center" bgcolor="coral">x</td><td>121</td><td align="center" bgcolor="coral">y</td><td>122</td><td align="center" bgcolor="coral">z</td><td>123</td><td align="center" bgcolor="lightblue">{</td><td>124 </td><td align="center" bgcolor="lightblue">|</td><td>125</td><td align="center" bgcolor="lightblue">}</td><td>126</td><td align="center" bgcolor="lightblue">~</td><td>127</td><td align="center" bgcolor="yellow">del</td>
</tr>
</tbody></table>
</div>
<br>
<br>
<h3>Hexadecimal</h3>
<div align="center">
<table border="2" cellpadding="3" width="600">
<tbody><tr>
<td>00</td><td align="center" bgcolor="yellow">nul</td><td>01</td><td align="center" bgcolor="yellow">soh</td><td>02</td><td align="center" bgcolor="yellow">stx</td><td>03</td><td align="center" bgcolor="yellow">etx</td><td>04</td><td align="center" bgcolor="yellow">eot</td><td>05</td><td align="center" bgcolor="yellow">enq</td><td>06</td><td align="center" bgcolor="yellow">ack</td><td>07</td><td align="center" bgcolor="yellow">bel</td>
</tr>
<tr>
<td>08</td><td align="center" bgcolor="yellow">bs</td><td>09</td><td align="center" bgcolor="yellow">tab</td><td>0a</td><td align="center" bgcolor="yellow">nl</td><td>0b</td><td align="center" bgcolor="yellow">vt</td><td>0c</td><td align="center" bgcolor="yellow">ff</td><td>0d</td><td align="center" bgcolor="yellow">cr</td><td>0e</td><td align="center" bgcolor="yellow">so</td><td>0f</td><td align="center" bgcolor="yellow">si</td>
</tr>
<tr>
<td>10</td><td align="center" bgcolor="yellow">dle</td><td>11</td><td align="center" bgcolor="yellow">dc1</td><td>12</td><td align="center" bgcolor="yellow">dc2</td><td>13</td><td align="center" bgcolor="yellow">dc3</td><td>14</td><td align="center" bgcolor="yellow">dc4</td><td>15</td><td align="center" bgcolor="yellow">nak</td><td>16</td><td align="center" bgcolor="yellow">syn</td><td>17</td><td align="center" bgcolor="yellow">etb</td>
</tr>
<tr>
<td>18</td><td align="center" bgcolor="yellow">can</td><td>19</td><td align="center" bgcolor="yellow">em</td><td>1a</td><td align="center" bgcolor="yellow">sub</td><td>1b</td><td align="center" bgcolor="yellow">esc</td><td>1c</td><td align="center" bgcolor="yellow">fs</td><td>1d</td><td align="center" bgcolor="yellow">gs</td><td>1e</td><td align="center" bgcolor="yellow">rs</td><td>1f</td><td align="center" bgcolor="yellow">us</td>
</tr>
<tr>
<td>20</td><td align="center" bgcolor="white">sp</td><td>21</td><td align="center" bgcolor="lightblue">!</td><td>22</td><td align="center" bgcolor="lightblue">"</td><td>23</td><td align="center" bgcolor="lightblue">#</td><td>24</td><td align="center" bgcolor="lightblue">$</td><td>25</td><td align="center" bgcolor="lightblue">%</td><td>26</td><td align="center" bgcolor="lightblue">&</td><td>27</td><td align="center" bgcolor="lightblue">'</td>
</tr>
<tr>
<td>28</td><td align="center" bgcolor="lightblue">(</td><td>29</td><td align="center" bgcolor="lightblue">)</td><td>2a</td><td align="center" bgcolor="lightblue">*</td><td>2b</td><td align="center" bgcolor="lightblue">+</td><td>2c</td><td align="center" bgcolor="lightblue">,</td><td>2d</td><td align="center" bgcolor="lightblue">-</td><td>2e</td><td align="center" bgcolor="lightblue">.</td><td>2f</td><td align="center" bgcolor="lightblue">/</td>
</tr>
<tr>
<td>30</td><td align="center" bgcolor="navajowhite">0</td><td>31</td><td align="center" bgcolor="navajowhite">1</td><td>32</td><td align="center" bgcolor="navajowhite">2</td><td>33</td><td align="center" bgcolor="navajowhite">3</td><td>34</td><td align="center" bgcolor="navajowhite">4</td><td>35</td><td align="center" bgcolor="navajowhite">5</td><td>36</td><td align="center" bgcolor="navajowhite">6</td><td>37</td><td align="center" bgcolor="navajowhite">7</td>
</tr>
<tr>
<td>38</td><td align="center" bgcolor="navajowhite">8</td><td>39</td><td align="center" bgcolor="navajowhite">9</td><td>3a</td><td align="center" bgcolor="lightblue">:</td><td>3b</td><td align="center" bgcolor="lightblue">;</td><td>3c</td><td align="center" bgcolor="lightblue"><</td><td>3d</td><td align="center" bgcolor="lightblue">=</td><td>3e</td><td align="center" bgcolor="lightblue">></td><td>3f</td><td align="center" bgcolor="lightblue">?</td>
</tr>
<tr>
<td>40</td><td align="center" bgcolor="lightblue">@</td><td>41</td><td align="center" bgcolor="lightgreen">A</td><td>42</td><td align="center" bgcolor="lightgreen">B</td><td>43</td><td align="center" bgcolor="lightgreen">C</td><td>44</td><td align="center" bgcolor="lightgreen">D</td><td>45</td><td align="center" bgcolor="lightgreen">E</td><td>46</td><td align="center" bgcolor="lightgreen">F</td><td>47</td><td align="center" bgcolor="lightgreen">G</td>
</tr>
<tr>
<td>48</td><td align="center" bgcolor="lightgreen">H</td><td>49</td><td align="center" bgcolor="lightgreen">I</td><td>4a</td><td align="center" bgcolor="lightgreen">J</td><td>4b</td><td align="center" bgcolor="lightgreen">K</td><td>4c</td><td align="center" bgcolor="lightgreen">L</td><td>4d</td><td align="center" bgcolor="lightgreen">M</td><td>4e</td><td align="center" bgcolor="lightgreen">N</td><td>4f</td><td align="center" bgcolor="lightgreen">O</td>
</tr>
<tr>
<td>50</td><td align="center" bgcolor="lightgreen">P</td><td>51</td><td align="center" bgcolor="lightgreen">Q</td><td>52</td><td align="center" bgcolor="lightgreen">R</td><td>53</td><td align="center" bgcolor="lightgreen">S</td><td>54</td><td align="center" bgcolor="lightgreen">T</td><td>55</td><td align="center" bgcolor="lightgreen">U</td><td>56</td><td align="center" bgcolor="lightgreen">V</td><td>57</td><td align="center" bgcolor="lightgreen">W</td>
</tr>
<tr>
<td>58</td><td align="center" bgcolor="lightgreen">X</td><td>59</td><td align="center" bgcolor="lightgreen">Y</td><td>5a</td><td align="center" bgcolor="lightgreen">Z</td><td>5b</td><td align="center" bgcolor="lightblue">[</td><td>5c</td><td align="center" bgcolor="lightblue">\</td><td>5d</td><td align="center" bgcolor="lightblue">]</td><td>5e</td><td align="center" bgcolor="lightblue">^</td><td>5f</td><td align="center" bgcolor="lightblue">_</td>
</tr>
<tr>
<td>60</td><td align="center" bgcolor="lightblue">`</td><td>61</td><td align="center" bgcolor="coral">a</td><td>62</td><td align="center" bgcolor="coral">b</td><td>63</td><td align="center" bgcolor="coral">c</td><td>64</td><td align="center" bgcolor="coral">d</td><td>65</td><td align="center" bgcolor="coral">e</td><td>66</td><td align="center" bgcolor="coral">f</td><td>67</td><td align="center" bgcolor="coral">g</td>
</tr>
<tr>
<td>68</td><td align="center" bgcolor="coral">h</td><td>69</td><td align="center" bgcolor="coral">i</td><td>6a</td><td align="center" bgcolor="coral">j</td><td>6b</td><td align="center" bgcolor="coral">k</td><td>6c</td><td align="center" bgcolor="coral">l</td><td>6d</td><td align="center" bgcolor="coral">m</td><td>6e</td><td align="center" bgcolor="coral">n</td><td>6f</td><td align="center" bgcolor="coral">o</td>
</tr>
<tr>
<td>70</td><td align="center" bgcolor="coral">p</td><td>71</td><td align="center" bgcolor="coral">q</td><td>72</td><td align="center" bgcolor="coral">r</td><td>73</td><td align="center" bgcolor="coral">s</td><td>74</td><td align="center" bgcolor="coral">t</td><td>75</td><td align="center" bgcolor="coral">u</td><td>76</td><td align="center" bgcolor="coral">v</td><td>77</td><td align="center" bgcolor="coral">w</td>
</tr>
<tr>
<td>78</td><td align="center" bgcolor="coral">x</td><td>79</td><td align="center" bgcolor="coral">y</td><td>7a</td><td align="center" bgcolor="coral">z</td><td>7b</td><td align="center" bgcolor="lightblue">{</td><td>7c</td><td align="center" bgcolor="lightblue">|</td><td>7d</td><td align="center" bgcolor="lightblue">}</td><td>7e</td><td align="center" bgcolor="lightblue">~</td><td>7f</td><td align="center" bgcolor="yellow">del</td>
</tr>
</tbody></table>
</div>
<br>
<br>
<h3>The POSIX Classes</h3>
<p>
The basic POSIX character classes are shown by color-coding as follows:
</p>
<center>
<table border="2" cellpadding="2"cellpadding="2">
<tr bgcolor="yellow"><td>Control Characters</td><td>[:cntrl:]</td></tr>
<tr bgcolor="white"><td >Space</td><td> </td></tr>
<tr bgcolor="lightblue"><td >Punctuation</td><td>[:punct:]</td></tr>
<tr bgcolor="navajowhite"><td >Digits</td><td>[:digit:]</td></tr>
<tr bgcolor="lightgreen"><td >Upper Case Letters</td><td>[:upper:]</td></tr>
<tr bgcolor="coral"><td >Lower Case Letters</td><td>[:lower:]</td></tr>
</table>
</center>
<br>
<p>
Notice that the space character stands on its own and is not included in any
basic class.
</p>
<P>
The usual derived classes are as follows.
</p>
<center>
<table border="2" cellspacing="2" cellpadding="2" bgcolor="navajowhite">
<tr><th>Class</th><th>Definition</th></tr>
<tr><td>[:alpha:]</td><td>[:upper:] ∪ [:lower:]</td></tr>
<tr><td>[:alnum:]</td><td>[:alpha:] ∪ [:digit:]</td></tr>
<tr><td>[:xdigit:]</td><td>[:digit:] ∪ [AaBbCcDdEeFf]</td></tr>
<tr><td>[:graph:]</td><td>[:alnum:] ∪ [:punct:]</td></tr>
<tr><td>[:print:]</td><td>[:graph:] ∪ Space </td></tr>
<tr><td>[:blank:]</td><td> Space ∪ Tab</td></tr>
<tr><td>[:space:]</td><td>[:blank:] ∪ [NL VT FF CR]</td></tr>
<tr><td>[:word:]</td><td>[:alnum:] ∪ Underscore</td></tr>
</table>
</center>
<P>
All but [:word:] are defined in the POSIX standard. [:word:] is not a POSIX
class (pace the bash manual) but reflects the fact that in quite a few
programming languages the characters in this class are those permitted in identifiers.
</p>
<P>
The principle governing the classification of characters outside the ASCII range
is that the structure of the system as applied to ASCII must be maintained, except
that additional classes may be created. The rules for the derived classes must
continue to hold, and the basic classes must remain disjoint.
</p>
<br>
<h3>The Control Characters</h3>
<P>
The first 31 characters (0-30 decimal, 000-037 octal, 0x00-0x1E hex) together with the
last character DEL (decimal 127, octal 177, hex 0x7F) are the "control
characters". These were originally used to control teletype machines. Only a few of them
are generally meaningful with most devices used today. However, they are often used
for other purposes, for example, as commands to programs. When you press the control key
on a keyboard at the same time as one of the letters, the code sent to the computer is
the corresponding control code. That is, CTRL-A sends 001, CTRL-B sends 002, CTRl-C sends
003, etc.
</p>
<P>
Most of the control characters should not appear in normal text. The ones that are likely
to are:
</p>
<center>
<table border="2" cellpadding="2"cellpadding="2" bgcolor="navajowhite">
<tr><td>0x09</td><td>TAB</td><td>horizontal tab</td></tr>
<tr><td>0x0A</td><td>NL</td><td>newline/linefeed</td></tr>
<tr><td>0x0D</td><td>CR</td><td>carriage return</td></tr>
</table>
</center>
<p>
Control characters are sometimes referred to by
names like "Control-A", also written "Ctrl-A" or "^A". The correspondance is
as follows: The null character, 0x00, is designated "Control-@". 0x01 is "Control-A",
0x02 is "Control-B", and so on through 0x1A, which is "Control-Z". 0x1B is "Control-[",
0x1C "Control-\", 0x1D "Control-]", 0x1E "Control-^", 0x1F "Control-_", and 0x20
"Control-`". In other words, the control characters are regarded as "Control" versions
of the range 0x40-0x60.
</p>
<P>
The original meanings of the control characters are as follows:
</p>
<P>
<DIV align="center">
<TABLE border="2" cellpadding="2" cellspacing="3" width="55%">
<TR><TD>ACK</TD><TD>acknowledge</TD></TR>
<TR><TD>BEL</TD><TD>bell - rings the bell</TD></TR>
<TR><TD>BS</TD><TD>backspace - moves the cursor or print head back one space</TD></TR>
<TR><TD>CAN</TD><TD>cancel</TD></TR>
<TR><TD>CR</TD><TD>carriage return - moves the cursor or print head back to the beginning of the line</TD></TR>
<TR><TD>DC1</TD><TD>device control 1</TD></TR>
<TR><TD>DC2</TD><TD>device control 2</TD></TR>
<TR><TD>DC3</TD><TD>device control 3</TD></TR>
<TR><TD>DC4</TD><TD>device control 4</TD></TR>
<TR><TD>DLE</TD><TD>data link escape</TD></TR>
<TR><TD>EM</TD><TD>end of medium</TD></TR>
<TR><TD>ENQ</TD><TD>enquiry</TD></TR>
<TR><TD>EOT</TD><TD>end of transmission</TD></TR>
<TR><TD>ESC</TD><TD>escape</TD></TR>
<TR><TD>ETB</TD><TD>end of transmission block</TD></TR>
<TR><TD>ETX</TD><TD>end of text</TD></TR>
<TR><TD>FF</TD><TD>form feed - advances the paper to the top of the next page</TD></TR>
<TR><TD>FS</TD><TD>file separator</TD></TR>
<TR><TD>GS</TD><TD>group separator</TD></TR>
<TR><TD>NAK</TD><TD>negative acknowledge</TD></TR>
<TR><TD>NL</TD><TD>newline. Also known as LF "line feed". Originally, moved the print head or cursor to the next line.</TD></TR>
<TR><TD>NUL</TD><TD>null</TD></TR>
<TR><TD>RS</TD><TD>record separator</TD></TR>
<TR><TD>SI</TD><TD>shift in - switches output device back to default character set</TD></TR>
<TR><TD>SO</TD><TD>shift out - switches output device to alternate character set</TD></TR>
<TR><TD>SOH</TD><TD>start of heading</TD></TR>
<TR><TD>STX</TD><TD>start of text</TD></TR>
<TR><TD>SUB</TD><TD>substitute</TD></TR>
<TR><TD>SYN</TD><TD>synchronous idle</TD></TR>
<TR><TD>TAB</TD><TD>horizontal tab</TD></TR>
<TR><TD>US</TD><TD>unit separator</TD></TR>
<TR><TD>VT</TD><TD>vertical tab</TD></TR>
</TABLE>
</DIV>
<br>
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<br>
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