Post History

Unix filters are quite handy.

First of all, you can get an index of any manual page with a simple *grep*(1):

```sh
$ man pacman | grep '^[^ ]'
PACMAN(8)                            Pacman Manual                           PACMAN(8)
NAME
SYNOPSIS
DESCRIPTION
OPERATIONS
OPTIONS
TRANSACTION OPTIONS (APPLY TO -S, -R AND -U)
UPGRADE OPTIONS (APPLY TO -S AND -U)
QUERY OPTIONS (APPLY TO -Q)
REMOVE OPTIONS (APPLY TO -R)
SYNC OPTIONS (APPLY TO -S)
DATABASE OPTIONS (APPLY TO -D)
FILE OPTIONS (APPLY TO -F)
HANDLING CONFIG FILES
EXAMPLES
CONFIGURATION
SEE ALSO
BUGS
AUTHORS
Pacman 6.0.2                          2023-08-16                             PACMAN(8)
```

If you also want to see subsections, you can expang that *grep*(1) a little bit:

```sh
$ man rsync | grep -e '^[^ ]' -e '^   [^ ]'
rsync(1)                             User Commands                            rsync(1)
NAME
SYNOPSIS
DESCRIPTION
GENERAL
SETUP
USAGE
COPYING TO A DIFFERENT NAME
SORTED TRANSFER ORDER
MULTI‐HOST SECURITY
ADVANCED USAGE
CONNECTING TO AN RSYNC DAEMON
USING RSYNC‐DAEMON FEATURES VIA A REMOTE‐SHELL CONNECTION
STARTING AN RSYNC DAEMON TO ACCEPT CONNECTIONS
EXAMPLES
OPTION SUMMARY
OPTIONS
DAEMON OPTIONS
FILTER RULES
   SIMPLE INCLUDE/EXCLUDE RULES
   SIMPLE INCLUDE/EXCLUDE EXAMPLE
   FILTER RULES WHEN DELETING
   FILTER RULES IN DEPTH
   PATTERN MATCHING RULES
   FILTER RULE MODIFIERS
   MERGE‐FILE FILTER RULES
   LIST‐CLEARING FILTER RULE
   ANCHORING INCLUDE/EXCLUDE PATTERNS
   PER‐DIRECTORY RULES AND DELETE
TRANSFER RULES
BATCH MODE
SYMBOLIC LINKS
DIAGNOSTICS
EXIT VALUES
ENVIRONMENT VARIABLES
FILES
SEE ALSO
BUGS
VERSION
INTERNAL OPTIONS
CREDITS
THANKS
AUTHOR
rsync 3.2.7                           20 Oct 2022                             rsync(1)
```

If you want to read only one of those sections, you can script a little bit more.  Let's say you're only interested in the SYNC OPTIONS from *pacman*(8).

```sh
$ man -w pacman \
  | xargs zcat \
  | pee 'sed -n "/^\.TH/,/^\.SH/{/^\.SH/!p}"' \
        'sed -n -e "/^\.SH \"\?SYNC OPTIONS/p" \
                -e "/^\.SH \"\?SYNC OPTIONS/,/^\.SH/{/^\.SH/!p}"' \
  |  groff -man -Tutf8;
PACMAN(8)                        Pacman Manual                       PACMAN(8)

SYNC OPTIONS (APPLY TO -S)
       -c, --clean
           Remove packages that are no longer installed from the cache as well
           as currently unused sync databases to free up disk space. When
           pacman downloads packages, it saves them in a cache directory. In
           addition, databases are saved for every sync DB you download from
           and are not deleted even if they are removed from the configuration
           file pacman.conf(5). Use one --clean switch to only remove packages
           that are no longer installed; use two to remove all files from the
           cache. In both cases, you will have a yes or no option to remove
           packages and/or unused downloaded databases.

           If you use a network shared cache, see the CleanMethod option in
           pacman.conf(5).

       -g, --groups
           Display all the members for each package group specified. If no
           group names are provided, all groups will be listed; pass the flag
           twice to view all groups and their members.

       -i, --info
           Display information on a given sync database package. Passing two
           --info or -i flags will also display those packages in all
           repositories that depend on this package.

       -l, --list
           List all packages in the specified repositories. Multiple
           repositories can be specified on the command line.

       -q, --quiet
           Show less information for certain sync operations. This is useful
           when pacman’s output is processed in a script. Search will only
           show package names and not repository, version, group, and
           description information; list will only show package names and omit
           databases and versions; group will only show package names and omit
           group names.

       -s, --search <regexp>
           This will search each package in the sync databases for names or
           descriptions that match regexp. When you include multiple search
           terms, only packages with descriptions matching ALL of those terms
           will be returned.

       -u, --sysupgrade
           Upgrades all packages that are out-of-date. Each
           currently-installed package will be examined and upgraded if a
           newer package exists. A report of all packages to upgrade will be
           presented, and the operation will not proceed without user
           confirmation. Dependencies are automatically resolved at this level
           and will be installed/upgraded if necessary.

           Pass this option twice to enable package downgrades; in this case,
           pacman will select sync packages whose versions do not match with
           the local versions. This can be useful when the user switches from
           a testing repository to a stable one.

           Additional targets can also be specified manually, so that -Su foo
           will do a system upgrade and install/upgrade the "foo" package in
           the same operation.

       -y, --refresh
           Download a fresh copy of the master package database from the
           server(s) defined in pacman.conf(5). This should typically be used
           each time you use --sysupgrade or -u. Passing two --refresh or -y
           flags will force a refresh of all package databases, even if they
           appear to be up-to-date.

Pacman 6.0.2                      2023-08-16                         PACMAN(8)
```

(If you want to get rid of the formatting, you can replace groff by mandoc in the pipeline.)

```sh
$ man -w pacman \
  | xargs zcat \
  | pee 'sed -n "/^\.TH/,/^\.SH/{/^\.SH/!p}"' \
        'sed -n -e "/^\.SH \"\?SYNC OPTIONS/p" \
                -e "/^\.SH \"\?SYNC OPTIONS/,/^\.SH/{/^\.SH/!p}"' \
  | groff -man -Tutf8\
  | mandoc -Tutf8 2>/dev/null \
  | col -pbx;
```

The origin of this script is in fact in the Linux man-pages repository (it's a bit different, as I deal with uncompressed pages, and often want to read the same section in several pages in the same directory).  I've used it for reviewing changes to the pages.
Here's the original code (see the `man_section()` function):
<https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/scripts/bash_aliases>



With more powerful scripts, you'll be able to do more powerful selections.