Anthony J. Bentley wrote in <2866-1680590811.027...@hnc7.hhyy.epmr>: |Ken Hornstein writes: |> Let's take the example you gave where the first line for a man |> page that uses tbl should contain: |> |> '\" t |> |> So, my question is ... what does this mean? I understand that \" is |> a comment, but I'm confused about the leading single quote. ... |As for why the 't' is there, it's strictly a manpage practice, not |a general roff authoring practice. man(1) peeks at the comment (man-db |does anyway; pretty sure mandoc doesn't need it) to determine which |preprocessors to run. E.g., a manual that needs the eqn preprocessor |would have an 'e' instead. | |Normally the person piping a document through troff would be the author, |and would already know that the document contains tables that require |the source to be preprocessed with tbl. But manuals are formatted by |users; the man(1) program doesn't know the document features in advance, |and wants to avoid running preprocessors unless they're necessary.
For example, newer man(1)s read the first line of the manual and check for a syntax <^'\" >followed by concat of [egprtv]+ (and in fact *join in* $MANROFFSEQ environment [egprtv]+) while getopts 'egprtv' preproc_arg; do case "${preproc_arg}" in e) pipeline="$pipeline | $EQN" ;; g) GRAP ;; # Ignore for compatibility. p) pipeline="$pipeline | $PIC" ;; r) pipeline="$pipeline | $REFER" ;; t) pipeline="$pipeline | $TBL" ;; v) pipeline="$pipeline | $VGRIND" ;; *) usage ;; esac --steffen | |Der Kragenbaer, The moon bear, |der holt sich munter he cheerfully and one by one |einen nach dem anderen runter wa.ks himself off |(By Robert Gernhardt)