Escape HTML special characters in awk - html

Question

From an awk script I want to generate a HTML file. My string could include characters like "<" and "&". Is there a short and proven function for awk which does the escaping?

Answer 1

Sure. Just call makeEntities() for each line ($0) you want to convert. Or modify it to accept an argument. I made this for working with the British National Corpus, which has a high degree of overlap with HTML entities, but not 100%, so if there are some exotic characters you need, you should verify that they are correct.
function makeEntities() {
gsub(/á/, "\\á");
gsub(/Á/, "\\Á");
gsub(/ă/, "\\ă");
gsub(/â/, "\\â");
gsub(/´/, "\\´");
gsub(/æ/, "\\æ");
gsub(/Æ/, "\\Æ");
gsub(/α/, "\\&agr;");
gsub(/à/, "\\à");
gsub(/ā/, "\\ā");
gsub(/Ā/, "\\Ā");
gsub(/&/, "\\&");
gsub(/ą/, "\\ą");
gsub(/å/, "\\å");
gsub(/Å/, "\\Å");
gsub(/ã/, "\\ã");
gsub(/ä/, "\\ä");
gsub(/Ä/, "\\Ä");
gsub(/β/, "\\&bgr;");
gsub(/\\/, "\\\");
gsub(/•/, "\\•");
gsub(/ć/, "\\ć");
gsub(/č/, "\\č");
gsub(/Č/, "\\Č");
gsub(/ç/, "\\ç");
gsub(/Ç/, "\\Ç");
gsub(/ĉ/, "\\ĉ");
gsub(/✓/, "\\✓");
gsub(/ˆ/, "\\ˆ");
gsub(/#/, "\\@");
gsub(/©/, "\\©");
gsub(/‐/, "\\‐");
gsub(/ď/, "\\ď");
gsub(/°/, "\\°");
gsub(/δ/, "\\&dgr;");
gsub(/Δ/, "\\&Dgr;");
gsub(/¨/, "\\¨");
gsub(/\$/, "\\$");
gsub(/đ/, "\\đ");
gsub(/é/, "\\é");
gsub(/É/, "\\É");
gsub(/ě/, "\\ě");
gsub(/ê/, "\\ê");
gsub(/è/, "\\è");
gsub(/È/, "\\È");
gsub(/ε/, "\\&egr;");
gsub(/ē/, "\\ē");
gsub(/Ē/, "\\Ē");
gsub(/ę/, "\\ę");
gsub(/ð/, "\\ð");
gsub(/ë/, "\\ë");
gsub(/Ë/, "\\Ë");
gsub(/♭/, "\\♭");
gsub(/½/, "\\½");
gsub(/⅓/, "\\⅓");
gsub(/¼/, "\\¼");
gsub(/⅕/, "\\⅕");
gsub(/⅙/, "\\⅙");
gsub(/⅛/, "\\⅛");
gsub(/⅔/, "\\⅔");
gsub(/⅖/, "\\⅖");
gsub(/¾/, "\\¾");
gsub(/⅗/, "\\⅗");
gsub(/⅜/, "\\⅜");
gsub(/⅘/, "\\⅘");
gsub(/⅝/, "\\⅝");
gsub(/⅞/, "\\⅞");
gsub(/′/, "\\&ft;");
gsub(/γ/, "\\&ggr;");
gsub(/>/, "\\>");
gsub(/½/, "\\½");
gsub(/ħ/, "\\ħ");
gsub(/í/, "\\í");
gsub(/Í/, "\\Í");
gsub(/î/, "\\î");
gsub(/Î/, "\\Î");
gsub(/ì/, "\\ì");
gsub(/ī/, "\\ī");
gsub(/″/, "\\&ins;");
gsub(/¿/, "\\¿");
gsub(/ï/, "\\ï");
gsub(/Ï/, "\\Ï");
gsub(/ĺ/, "\\ĺ");
gsub(/Ĺ/, "\\Ĺ");
gsub(/\{/, "\\{");
gsub(/≤/, "\\≤");
gsub(/λ/, "\\&lgr;");
gsub(/_/, "\\_");
gsub(/\[/, "\\[");
gsub(/ł/, "\\ł");
gsub(/Ł/, "\\Ł");
gsub(/</, "\\<");
gsub(/—/, "\\—");
gsub(/μ/, "\\&mgr;");
gsub(/µ/, "\\µ");
gsub(/·/, "\\·");
gsub(/ń/, "\\&nacute;");
gsub(/ň/, "\\&ncaron;");
gsub(/ņ/, "\\&ncedil;");
gsub(/–/, "\\–");
gsub(/ñ/, "\\ñ");
gsub(/Ñ/, "\\Ñ");
gsub(/#/, "\\&num;");
gsub(/ó/, "\\ó");
gsub(/Ó/, "\\Ó");
gsub(/ô/, "\\ô");
gsub(/œ/, "\\œ");
gsub(/ò/, "\\ò");
gsub(/Ω/, "\\&ohm;");
gsub(/ō/, "\\&omacr;");
gsub(/ø/, "\\ø");
gsub(/Ø/, "\\Ø");
gsub(/õ/, "\\õ");
gsub(/ö/, "\\ö");
gsub(/Ö/, "\\Ö");
gsub(/φ/, "\\&phgr;");
gsub(/\+/, "\\&plus;");
gsub(/±/, "\\±");
gsub(/£/, "\\£");
gsub(/ŕ/, "\\&racute;");
gsub(/√/, "\\√");
gsub(/ř/, "\\&rcaron;");
gsub(/Ř/, "\\&Rcaron;");
gsub(/\}/, "\\&rcub;");
gsub(/®/, "\\®");
gsub(/-/, "\\&rehy;");
gsub(/\]/, "\\&rsqb;");
gsub(/ś/, "\\&sacute;");
gsub(/Ś/, "\\&Sacute;");
gsub(/š/, "\\š");
gsub(/Š/, "\\Š");
gsub(/ş/, "\\&scedil;");
gsub(/Ş/, "\\&Scedil;");
gsub(/ŝ/, "\\&scirc;");
gsub(/σ/, "\\&sgr;");
gsub(/♯/, "\\&sharp;");
gsub(/\//, "\\&shilling;");
gsub(/∼/, "\\∼");
gsub(/\//, "\\&sol;");
gsub(/²/, "\\²");
gsub(/ß/, "\\ß");
gsub(/ť/, "\\&tcaron;");
gsub(/ţ/, "\\&tcedil;");
gsub(/τ/, "\\&tgr;");
gsub(/þ/, "\\þ");
gsub(/Þ/, "\\Þ");
gsub(/×/, "\\×");
gsub(/™/, "\\™");
gsub(/ú/, "\\ú");
gsub(/Ú/, "\\Ú");
gsub(/û/, "\\û");
gsub(/ù/, "\\ù");
gsub(/ū/, "\\&umacr;");
gsub(/¨/, "\\¨");
gsub(/ů/, "\\&uring;");
gsub(/ü/, "\\ü");
gsub(/Ü/, "\\Ü");
gsub(/\|/, "\\&verbar;");
gsub(/ŵ/, "\\&wcirc;");
gsub(/ý/, "\\ý");
gsub(/ŷ/, "\\&ycirc;");
gsub(/¥/, "\\¥");
gsub(/ÿ/, "\\ÿ");
gsub(/Ÿ/, "\\Ÿ");
gsub(/ź/, "\\&zacute;");
gsub(/Ž/, "\\&Zcaron;");
gsub(/ž/, "\\&zcaron;");
gsub(/ż/, "\\&zdot;");
}

Answer 2

To escape the bare minimum you can do:
function escapeHtml(t)
{
# Must do this one first
gsub(/&/, "\\&", t);
gsub(/</, "\\<", t);
gsub(/>/, "\\>", t);
return t;
}