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Less-than sign
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<h2 id="computing">Computing</h2> <p>The less-than sign, <, is an original <a href="/facts/ASCII/vGUI33Qu">ASCII</a> character (hex 3C, decimal 60). </p> <h3>Programming</h3> <p>In <a href="/facts/BASIC/VYMl5TmA">BASIC</a>, <a href="/facts/Lisp_(programming_language)/xJHA3CrX">Lisp</a>-family languages, and <a href="/facts/C_(programming_language)/Ky2No763">C</a>-family languages (including <a href="/facts/Java_(programming_language)/9ScgFyAL">Java</a> and <a href="/facts/C%252B%252B/Et0F2qn9">C++</a>), <a href="/facts/Operator_(computing)/7TnU5LKu">comparison operator</a> < means "less than". </p><p>In <a href="/facts/Coldfusion/4WB5vcA2">Coldfusion</a>, operator .lt. means "less than". </p><p>In <a href="/facts/Fortran/m1KqjcMU">Fortran</a>, operator .LT. means "less than"; later versions allow <. </p> <h4>Shell scripts</h4> <p>In <a href="/facts/Bourne_shell/wUCh3Qkl">Bourne shell</a> (and many other shells), operator -lt means "less than". Less-than sign is used to <a href="/facts/Redirection_(computing)/0qhx445L">redirect</a> input from a file. Less-than plus ampersand (<&) is used to redirect from a <a href="/facts/File_descriptor/Iw74UKqG">file descriptor</a>. </p> <h4>Double less-than sign</h4> <p>The double less-than sign, <<, may be used for an approximation of the <i>much-less-than sign</i> (≪) or of the opening <a href="/facts/Guillemet/cfjrC79a">guillemet</a> («). ASCII does not encode either of these signs, though they are both included in <a href="/facts/Unicode/DDu3MfPV">Unicode</a>. </p><p>In <a href="/facts/Bash_(Unix_shell)/RrYLtEJT">Bash</a>, <a href="/facts/Perl/fx31kjlT">Perl</a>, and <a href="/facts/Ruby_(programming_language)/BeYSaPSR">Ruby</a>, operator <<EOF (where "EOF" is an arbitrary string, but commonly "EOF" denoting "end of file") is used to denote the beginning of a <a href="/facts/Here_document/7GJs16sB">here document</a>. </p><p>In <a href="/facts/C_(programming_language)/Ky2No763">C</a> and <a href="/facts/C%252B%252B/Et0F2qn9">C++</a>, operator << represents a <a href="/facts/Bitwise_operation/0gkqnUda">binary left shift</a>. </p><p>In the <a href="/facts/C%252B%252B_Standard_Library/A5vQNSAD">C++ Standard Library</a>, operator <<, when applied on an output stream, acts as <i>insertion operator</i> and performs an output operation on the stream. </p><p>In <a href="/facts/Ruby_(programming_language)/BeYSaPSR">Ruby</a>, operator << acts as <i>append operator</i> when used between an array and the value to be appended. </p><p>In <a href="/facts/XPath/0eCtJoj7">XPath</a> the << operator returns true if the left operand precedes the right operand in document order; otherwise it returns false.<a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a> </p> <h4>Triple less-than sign</h4> <p>In <a href="/facts/PHP/vU6YRJX0">PHP</a>, operator <<<OUTPUT is used to denote the beginning of a <a href="/facts/Here_document/7GJs16sB">heredoc</a> statement (where OUTPUT is an arbitrary named variable.) </p><p>In Bash, <<<word is used as a "here string", where word is expanded and supplied to the command on its standard input, similar to a heredoc. </p> <h4>Less-than sign with equals sign</h4> <p>The less-than sign with the equals sign, <=, may be used for an approximation of the <a href="/facts/Inequality_(mathematics)/qkze4zdI">less-than-or-equal-to sign</a>, ≤. ASCII does not have a less-than-or-equal-to sign, but <a href="/facts/Unicode/DDu3MfPV">Unicode</a> defines it at code point U+2264. </p><p>In <a href="/facts/BASIC/VYMl5TmA">BASIC</a>, <a href="/facts/Lisp_(programming_language)/xJHA3CrX">Lisp</a>-family languages, and <a href="/facts/C_(programming_language)/Ky2No763">C</a>-family languages (including <a href="/facts/Java_(programming_language)/9ScgFyAL">Java</a> and <a href="/facts/C%252B%252B/Et0F2qn9">C++</a>), operator <= means "less than or equal to". In <a href="/facts/Sinclair_BASIC/NCnAcdR3">Sinclair BASIC</a> it is encoded as a single-byte code point token. </p><p>In <a href="/facts/Prolog/r5h66Qh1">Prolog</a>, =< means "less than or equal to" (as distinct from the arrow <=). </p><p>In <a href="/facts/Fortran/m1KqjcMU">Fortran</a>, operators .LE. and <= both mean "less than or equal to". </p><p>In <a href="/facts/Bourne_shell/wUCh3Qkl">Bourne shell</a> and <a href="/facts/Windows_PowerShell/G1d10lwn">Windows PowerShell</a>, the operator -le means "less than or equal to". </p> <h4>Less-than sign with hyphen-minus</h4> <p>In the <a href="/facts/R_(programming_language)/LSrkr8K8">R programming language</a>, the less-than sign is used in conjunction with a <a href="/facts/Hyphen-minus/TnWuz7hd">hyphen-minus</a> to create an arrow (<-), this can be used as the left assignment operator. </p> <h4>Spaceship operator</h4> <p>The less-than sign is used in the <a href="/facts/Spaceship_operator/3yHfCsLS">spaceship operator</a>. </p> <h4>HTML</h4> <p>In <a href="/facts/HTML/sSc3fT78">HTML</a> (and <a href="/facts/Standard_Generalized_Markup_Language/euIKXwHV">SGML</a> and <a href="/facts/XML/clNgUfWk">XML</a>), the less-than sign is used at the beginning of tags. The less-than sign may be included with <. The less-than-or-equal-to sign, ≤, may be included with ≤. </p> <h2 id="unicode">Unicode</h2> <p><a href="/facts/Unicode/DDu3MfPV">Unicode</a> provides various <i>less than</i> symbols:<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a> </p> <table><tbody><tr><th>Symbol</th><th>Unicode name</th><th>Code Point</th></tr><tr><td><</td><td>LESS-THAN SIGN</td><td>U+003C</td></tr><tr><td>≤</td><td>LESS-THAN OR EQUAL TO</td><td>U+2264</td></tr><tr><td>≦</td><td>LESS-THAN OVER EQUAL TO</td><td>U+2266</td></tr><tr><td>≨</td><td>LESS-THAN BUT NOT EQUAL TO</td><td>U+2268</td></tr><tr><td>≪</td><td>MUCH LESS-THAN</td><td>U+226A</td></tr><tr><td>≮</td><td>NOT LESS THAN</td><td>U+226E</td></tr><tr><td>≰</td><td>NEITHER LESS-THAN NOR EQUAL TO</td><td>U+2270</td></tr><tr><td>≲</td><td>LESS-THAN OR EQUIVALENT TO</td><td>U+2272</td></tr><tr><td>≴</td><td>NEITHER LESS-THAN NOR EQUIVALENT TO</td><td>U+2274</td></tr><tr><td>⋖</td><td>LESS-THAN WITH DOT</td><td>U+22D6</td></tr><tr><td>⋘</td><td>VERY MUCH LESS-THAN</td><td>U+22D8</td></tr><tr><td>⋜</td><td>EQUAL TO OR LESS-THAN</td><td>U+22DC</td></tr><tr><td>⋦</td><td>LESS-THAN BUT NOT EQUIVALENT TO</td><td>U+22E6</td></tr><tr><td>⍃</td><td>APL FUNCTIONAL SYMBOL QUAD LESS-THAN</td><td>U+2343</td></tr><tr><td>⥶</td><td>LESS-THAN ABOVE LEFTWARDS ARROW</td><td>U+2976</td></tr><tr><td>⥷</td><td>LEFTWARDS ARROW THROUGH LESS-THAN</td><td>U+2977</td></tr><tr><td>⦓</td><td>LEFT ARC LESS-THAN BRACKET</td><td>U+2993</td></tr><tr><td>⦖</td><td>DOUBLE RIGHT ARC LESS-THAN BRACKET</td><td>U+2996</td></tr><tr><td>⧀</td><td>CIRCLED LESS-THAN</td><td>U+29C0</td></tr><tr><td>⩹</td><td>LESS-THAN WITH CIRCLE INSIDE</td><td>U+2A79</td></tr><tr><td>⩻</td><td>LESS-THAN WITH QUESTION MARK ABOVE</td><td>U+2A7B</td></tr><tr><td>⩽</td><td>LESS-THAN OR SLANTED EQUAL TO</td><td>U+2A7D</td></tr><tr><td>⩿</td><td>LESS-THAN OR SLANTED EQUAL TO WITH DOT INSIDE</td><td>U+2A7F</td></tr><tr><td>⪁</td><td>LESS-THAN OR SLANTED EQUAL TO WITH DOT ABOVE</td><td>U+2A81</td></tr><tr><td>⪃</td><td>LESS-THAN OR SLANTED EQUAL TO WITH DOT ABOVE RIGHT</td><td>U+2A83</td></tr><tr><td>⪅</td><td>LESS-THAN OR APPROXIMATE</td><td>U+2A85</td></tr><tr><td>⪇</td><td>LESS-THAN AND SINGLE-LINE NOT EQUAL TO</td><td>U+2A87</td></tr><tr><td>⪉</td><td>LESS-THAN AND NOT APPROXIMATE</td><td>U+2A89</td></tr><tr><td>⪍</td><td>LESS-THAN ABOVE SIMILAR OR EQUAL</td><td>U+2A8D</td></tr><tr><td>⪕</td><td>SLANTED EQUAL OR LESS-THAN</td><td>U+2A95</td></tr><tr><td>⪗</td><td>SLANTED EQUAL OR LESS-THAN WITH DOT INSIDE</td><td>U+2A97</td></tr><tr><td>⪙</td><td>DOUBLE-LINE EQUAL TO OR LESS-THAN</td><td>U+2A99</td></tr><tr><td>⪛</td><td>DOUBLE-LINE SLANTED EQUAL TO OR LESS-THAN</td><td>U+2A9B</td></tr><tr><td>⪝</td><td>SIMILAR TO OR LESS-THAN</td><td>U+2A9D</td></tr><tr><td>⪟</td><td>SIMILAR ABOVE LESS-THAN ABOVE EQUALS SIGN</td><td>U+2A9F</td></tr><tr><td>⪡</td><td>DOUBLE NESTED LESS-THAN</td><td>U+2AA1</td></tr><tr><td>⪣</td><td>DOUBLE NESTED LESS-THAN WITH UNDERBAR</td><td>U+2AA3</td></tr><tr><td>⪦</td><td>LESS-THAN CLOSED BY CURVE</td><td>U+2AA6</td></tr><tr><td>⪨</td><td>LESS-THAN CLOSED BY CURVE ABOVE SLANTED EQUAL</td><td>U+2AA8</td></tr><tr><td>⫷</td><td>TRIPLE NESTED LESS-THAN</td><td>U+2AF7</td></tr><tr><td>⫹</td><td>DOUBLE-LINE SLANTED LESS-THAN OR EQUAL TO</td><td>U+2AF9</td></tr><tr><td>﹤</td><td>SMALL LESS-THAN SIGN</td><td>U+FE64</td></tr><tr><td>＜</td><td>FULLWIDTH LESS-THAN</td><td>U+FF1C</td></tr></tbody></table> <p>The less-than sign may be seen for an approximation of the opening <a href="/facts/Bracket/yzGM9J8A">angle bracket</a>, ⟨. True angle bracket characters, as required in <a href="/facts/Notation/IkqYLL0X">linguistics notation</a>, are expected in formal texts. </p> <h2 id="mathematics">Mathematics</h2> <p>In an inequality, the less-than sign and greater-than sign always "point" to the smaller number. Put another way, the "jaws" (the wider section of the symbol) always direct to the larger number. </p><p>The less-than-sign is sometimes used to represent a <a href="/facts/Total_order/xnTtmuYJ">total order</a>, <a href="/facts/Partial_order/qb4a3FAX">partial order</a> or <a href="/facts/Preorder/uubzHSWm">preorder</a>. However, the symbol ≺ {\displaystyle \prec } is often used when it would be confusing or not convenient to use <. In mathematical writing using <a href="/facts/LaTeX/c1lvjF0A">LaTeX</a>, the <a href="/facts/TeX/HDrl3Yvd">TeX</a> command is \prec. The Unicode <a href="/facts/Code_point/R184ugJX">code point</a> is U+227A ≺ PRECEDES. </p> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Inequality_(mathematics)/qkze4zdI">Inequality (mathematics)</a></li> <li><a href="/facts/Greater-than_sign/J58SE7bT">Greater-than sign</a></li> <li><a href="/facts/Relational_operator/nTXrhxN2">Relational operator</a></li> <li><a href="/facts/Much-less-than_sign/qkze4zdI">Much-less-than sign</a></li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>"XML Path Language (XPath) 2.0 (Second Edition)". www.w3.org. W3C. 14 December 2010. Archived from the original on 7 October 2022. Retrieved 29 October 2019. <a href="https://web.archive.org/web/20221007124416/https://www.w3.org/TR/xpath20/#id-node-comparisons" target="_blank">https://web.archive.org/web/20221007124416/https://www.w3.org/TR/xpath20/#id-node-comparisons</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>"Less than symbol". Archived from the original on 2023-05-16. Retrieved 2023-06-06. <a href="https://lessthansymbol.com/" target="_blank">https://lessthansymbol.com/</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> </ol>