How to search a pattern containing hyphens inside man pages

man

I'm trying to find a command to search for a pattern containing hyphens inside all man pages.

I've looked at man man, and found these 3 options:

-K, --global-apropos

Search for text in all manual pages. This is a brute-force search, and is likely to take some time;
if you can, you should specify a section to reduce the number of pages that need to be searched.
Search terms may be simple strings (the default), or regular expressions if the --regex option is
used.

-w, --where, --path, --location

Don't actually display the manual pages, but do print the location(s) of the source nroff files that
would be formatted.

-S list, -s list, t--sections=list

List is a colon- or comma-separated list of order specific manual sections to search. This option
overrides the $MANSECT environment variable. (The -s spelling is for compatibility with System V.)

I've tried to combine them to search for the pattern mark-modified-lines which is a readline option described in man bash:

$ man -s1 -Kw mark-modified-lines

But it doesn't find any page:

No manual entry for mark-modified-lines

And the command exits with the code 16.
I thought that maybe the syntax of the command was wrong, but it doesn't seem so, since this command correctly finds the 5 man pages on my system which contains the word guitar:

$ man -s1 -Kw guitar

  /usr/share/man/man1/ffmpeg-all.1.gz
  /usr/share/man/man1/ffserver-all.1.gz
  /usr/share/man/man1/ffplay-all.1.gz
  /usr/share/man/man1/ffmpeg-filters.1.gz
  /usr/share/man/man1/ffprobe-all.1.gz

I thought that maybe the hyphens in the word caused an issue.
In man bash, I found the --regex option which is described as follows:

--regex

Show all pages with any part of either their names or their descriptions matching each page argument
as a regular expression, as with apropos(1). Since there is usually no reasonable way to pick a
"best" page when searching for a regular expression, this option implies -a.

I tried to use this option and replace the word mark-modified-lines with the regex mark.modified.lines, where the hyphens are themselves replaced with the metacharacter . which should match any character:

$ man -s1 -Kw --regex 'mark.modified.lines'

It still doesn't print any page, while I know that the text is written in the bash man page.

The metacharacter . in the regex seems to be parsed as expected, since this command:

$ man -s1 -Kw --regex 'mark.mo'

Prints:

  /usr/share/man/man1/x11perfcomp.1.gz
  /usr/share/man/man1/xditview.1.gz

And these 2 manpages (x11perfcomp, xditview) are both matched by the regex mark.mo.
More specifically, man x11perfcomp contains this line:

Mark Moraes wrote the original scripts to compare servers.
^^^^^^^

And man xditview contains this line:

    Mark Moraes (University of Toronto)
    ^^^^^^^

However, man -s1 -Kw --regex 'mark.mo' doesn't print the bash man page:

/usr/share/man/man1/bash.1.gz

While I expected it would, since it contains this line:

mark-modified-lines (Off)
^^^^^^^

Is it possible to search for a pattern containing hyphens inside the man pages?

Best Answer

man -K searches the source code of the manual pages, not their rendered form (as displayed by man). Hyphens are encoded \-, so you need to search for that:

man -s1 -Kw 'mark\-mo'

Yes, this is rather obscure. The man man page mentions, in the description of the -K option, that

Note that this searches the sources of the manual pages, not the rendered text, and so may include false positives due to things like comments in source files. Searching the rendered text would be much slower.

but using this correctly involves knowing the source representation of the text you’re searching for.

Answer

Somebody installed both 64bit and 32bit version of glibc, which brings chaos I guess. After uninstall the 32bit version and reinstall 64bit version of glibc, man works.

== Detailed process ==

Ran mandb -t, lots of error messages showed up:

iconv_open ("UTF-8//IGNORE", "ISO-8859-1"): Invalid argument

By google I found that iconv_open is in gconv(ref).
strace mandb -t and strace man ls both show this information:

open("/usr/lib64/gconv/gconv-modules.cache", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib64/gconv/gconv-modules", O_RDONLY) = -1 ENOENT (No such file or directory)

By google I found that gconv-modules may be very important to iconv, which might be very important to man. And gconv is in glibc, now the best guess is that my glibc is not installed correctly.
Ran rpm -qa | grep glibc, I got this:

glibc-i18ndata-2.11.1-0.17.4
glibc-locale-2.11.1-0.17.4
glibc-info-2.11.1-0.17.4
glibc-html-2.11.1-0.17.4
glibc-profile-2.11.1-0.17.4
glibc-devel-2.11.1-0.17.4
glibc-2.11.1-0.17.4
glibc-32bit-2.11.1-0.17.4
glibc-devel-32bit-2.11.1-0.17.4
glibc-locale-32bit-2.11.1-0.17.4
glibc-profile-32bit-2.11.1-0.17.4

Ran rpm -e --nodeps 32bit-PACKAGE to remove all the 32bit packages, then reboot the machine(Any other way beside reboot?).
Reinstalled all the 64bit glibc packages.
man ls, it worked!

Why Shell Builtins Lack Proper Man Pages

Because builtins are part of the shell. Any bugs or history they have are bugs and history of the shell itself. They are not independent commands and don't exist outside the shell they are built into.

The equivalent, for bash at least, is the help command. For example:

$ help while
while: while COMMANDS; do COMMANDS; done
    Execute commands as long as a test succeeds.

    Expand and execute COMMANDS as long as the final command in the
    `while' COMMANDS has an exit status of zero.

    Exit Status:
    Returns the status of the last command executed.

All bash builtins have help pages. Even help itself:

$ help help
help: help [-dms] [pattern ...]
    Display information about builtin commands.

    Displays brief summaries of builtin commands.  If PATTERN is
    specified, gives detailed help on all commands matching PATTERN,
    otherwise the list of help topics is printed.

    Options:
      -d    output short description for each topic
      -m    display usage in pseudo-manpage format
      -s    output only a short usage synopsis for each topic matching
        PATTERN

    Arguments:
      PATTERN   Pattern specifiying a help topic

    Exit Status:
    Returns success unless PATTERN is not found or an invalid option is given.

Inspired by @mikeserv's sed script, here's a little function that will print the relevant section of a man page using Perl. Add this line to your shell's initialization file (~/.bashrc for bash):

manperl(){ man "$1" | perl -00ne "print if /^\s*$2\b/"; }

Then, you run it by giving it a man page and the name of a section:

$ manperl bash while
       while list-1; do list-2; done
       until list-1; do list-2; done
              The while command continuously executes the list list-2 as long as the last command in the list list-1 returns an exit
              status of zero.  The until command is identical to the while command, except that the test is negated; list-2 is  exe‐
              cuted  as  long  as the last command in list-1 returns a non-zero exit status.  The exit status of the while and until
              commands is the exit status of the last command executed in list-2, or zero if none was executed.

$ manperl grep SYNOPSIS
SYNOPSIS
       grep [OPTIONS] PATTERN [FILE...]
       grep [OPTIONS] [-e PATTERN | -f FILE] [FILE...]

$ manperl rsync "-r"
       -r, --recursive
              This tells rsync to copy directories recursively.  See also --dirs (-d).

Best Answer

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