lex: split posix, bsd and linux (#10001)

pages/common/lex.md

@@ -10,8 +10,8 @@
 
 - Specify the output file:
 
-`lex {{analyzer.l}} --outfile {{analyzer.c}}`
+`lex -t {{analyzer.l}} > {{analyzer.c}}`
 
 - Compile a C file generated by Lex:
 
-`cc {{path/to/lex.yy.c}} --output {{executable}}`
+`c99 {{path/to/lex.yy.c}} -o {{executable}}`

pages/linux/lex.md

@@ -0,0 +1,17 @@
+# lex
+
+> Lexical analyzer generator.
+> Given the specification for a lexical analyzer, generates C code implementing it.
+> More information: <https://manned.org/lex.1>.
+
+- Generate an analyzer from a Lex file:
+
+`lex {{analyzer.l}}`
+
+- Specify the output file:
+
+`lex {{analyzer.l}} --outfile {{analyzer.c}}`
+
+- Compile a C file generated by Lex:
+
+`cc {{path/to/lex.yy.c}} --output {{executable}}`

pages/osx/lex.md

@@ -0,0 +1,17 @@
+# lex
+
+> Lexical analyzer generator.
+> Given the specification for a lexical analyzer, generates C code implementing it.
+> More information: <https://keith.github.io/xcode-man-pages/lex.1.html>.
+
+- Generate an analyzer from a Lex file:
+
+`lex {{analyzer.l}}`
+
+- Specify the output file:
+
+`lex {{analyzer.l}} --outfile {{analyzer.c}}`
+
+- Compile a C file generated by Lex:
+
+`cc {{path/to/lex.yy.c}} --output {{executable}}`