В Mac OS кодировка должна быть в верхнем регистре:
bash-4.4$ less --version
less 458 (POSIX regular expressions)
Copyright (C) 1984-2012 Mark Nudelman
bash-4.4$ LESSCHARSET=cp1251 less
invalid charset name
bash-4.4$ LESSCHARSET=CP1251 less
Missing filename ("less --help" for help)
Здесь Я нашел список кодировок:
{ "ascii", NULL, "8bcccbcc18b95.b" },
{ "utf-8", &utf_mode, "8bcccbcc18b95.b126.bb" },
{ "iso8859", NULL, "8bcccbcc18b95.33b." },
{ "latin3", NULL, "8bcccbcc18b95.33b5.b8.b15.b4.b12.b18.b12.b." },
{ "arabic", NULL, "8bcccbcc18b95.33b.3b.7b2.13b.3b.b26.5b19.b" },
{ "greek", NULL, "8bcccbcc18b95.33b4.2b4.b3.b35.b44.b" },
{ "greek2005", NULL, "8bcccbcc18b95.33b14.b35.b44.b" },
{ "hebrew", NULL, "8bcccbcc18b95.33b.b29.32b28.2b2.b" },
{ "koi8-r", NULL, "8bcccbcc18b95.b." },
{ "KOI8-T", NULL, "8bcccbcc18b95.b8.b6.b8.b.b.5b7.3b4.b4.b3.b.b.3b." },
{ "georgianps", NULL, "8bcccbcc18b95.3b11.4b12.2b." },
{ "tcvn", NULL, "b..b...bcccbccbbb7.8b95.b48.5b." },
{ "TIS-620", NULL, "8bcccbcc18b95.b.4b.11b7.8b." },
{ "next", NULL, "8bcccbcc18b95.bb125.bb" },
{ "dos", NULL, "8bcccbcc12bc5b95.b." },
{ "windows-1251", NULL, "8bcccbcc12bc5b95.b24.b." },
{ "windows-1252", NULL, "8bcccbcc12bc5b95.b.b11.b.2b12.b." },
{ "windows-1255", NULL, "8bcccbcc12bc5b95.b.b8.b.5b9.b.4b." },
{ "ebcdic", NULL, "5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b." },
{ "IBM-1047", NULL, "4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc191.b" },
{ NULL, NULL, NULL }
и их псевдонимы:
{ "UTF-8", "utf-8" },
{ "ANSI_X3.4-1968", "ascii" },
{ "US-ASCII", "ascii" },
{ "latin1", "iso8859" },
{ "ISO-8859-1", "iso8859" },
{ "latin9", "iso8859" },
{ "ISO-8859-15", "iso8859" },
{ "latin2", "iso8859" },
{ "ISO-8859-2", "iso8859" },
{ "ISO-8859-3", "latin3" },
{ "latin4", "iso8859" },
{ "ISO-8859-4", "iso8859" },
{ "cyrillic", "iso8859" },
{ "ISO-8859-5", "iso8859" },
{ "ISO-8859-6", "arabic" },
{ "ISO-8859-7", "greek" },
{ "IBM9005", "greek2005" },
{ "ISO-8859-8", "hebrew" },
{ "latin5", "iso8859" },
{ "ISO-8859-9", "iso8859" },
{ "latin6", "iso8859" },
{ "ISO-8859-10", "iso8859" },
{ "latin7", "iso8859" },
{ "ISO-8859-13", "iso8859" },
{ "latin8", "iso8859" },
{ "ISO-8859-14", "iso8859" },
{ "latin10", "iso8859" },
{ "ISO-8859-16", "iso8859" },
{ "IBM437", "dos" },
{ "EBCDIC-US", "ebcdic" },
{ "IBM1047", "IBM-1047" },
{ "KOI8-R", "koi8-r" },
{ "KOI8-U", "koi8-r" },
{ "GEORGIAN-PS", "georgianps" },
{ "TCVN5712-1", "tcvn" },
{ "NEXTSTEP", "next" },
{ "windows", "windows-1252" }, /* backward compatibility */
{ "CP1251", "windows-1251" },
{ "CP1252", "windows-1252" },
{ "CP1255", "windows-1255" },
{ NULL, NULL }