1MAN(1)                        Manual pager utils                        MAN(1)
2
3
4

NAME

6       man - an interface to the system reference manuals
7

SYNOPSIS

9       man [man options] [[section] page ...] ...
10       man -k [apropos options] regexp ...
11       man -K [man options] [section] term ...
12       man -f [whatis options] page ...
13       man -l [man options] file ...
14       man -w|-W [man options] page ...
15

DESCRIPTION

17       man  is  the system's manual pager.  Each page argument given to man is
18       normally the name of a program, utility or function.  The  manual  page
19       associated with each of these arguments is then found and displayed.  A
20       section, if provided, will direct man to look only in that  section  of
21       the  manual.   The  default action is to search in all of the available
22       sections following a pre-defined order (see DEFAULTS), and to show only
23       the first page found, even if page exists in several sections.
24
25       The table below shows the section numbers of the manual followed by the
26       types of pages they contain.
27
28
29       1   Executable programs or shell commands
30       2   System calls (functions provided by the kernel)
31       3   Library calls (functions within program libraries)
32       4   Special files (usually found in /dev)
33       5   File formats and conventions, e.g. /etc/passwd
34       6   Games
35       7   Miscellaneous (including  macro  packages  and  conventions),  e.g.
36           man(7), groff(7), man-pages(7)
37       8   System administration commands (usually only for root)
38       9   Kernel routines [Non standard]
39
40       A manual page consists of several sections.
41
42       Conventional  section  names include NAME, SYNOPSIS, CONFIGURATION, DE‐
43       SCRIPTION, OPTIONS,  EXIT STATUS,  RETURN VALUE,  ERRORS,  ENVIRONMENT,
44       FILES,  VERSIONS,  CONFORMING TO,  NOTES,  BUGS,  EXAMPLE, AUTHORS, and
45       SEE ALSO.
46
47       The following conventions apply to the SYNOPSIS section and can be used
48       as a guide in other sections.
49
50
51       bold text          type exactly as shown.
52       italic text        replace with appropriate argument.
53       [-abc]             any or all arguments within [ ] are optional.
54       -a|-b              options delimited by | cannot be used together.
55       argument ...       argument is repeatable.
56       [expression] ...   entire expression within [ ] is repeatable.
57
58       Exact rendering may vary depending on the output device.  For instance,
59       man will usually not be able to render italics when running in a termi‐
60       nal, and will typically use underlined or coloured text instead.
61
62       The command or function illustration is a pattern that should match all
63       possible invocations.  In some cases it is advisable to illustrate sev‐
64       eral  exclusive invocations as is shown in the SYNOPSIS section of this
65       manual page.
66

EXAMPLES

68       man ls
69           Display the manual page for the item (program) ls.
70
71       man man.7
72           Display the manual page for  macro  package  man  from  section  7.
73           (This is an alternative spelling of "man 7 man".)
74
75       man 'man(7)'
76           Display  the  manual  page  for  macro  package man from section 7.
77           (This is another alternative spelling of "man 7 man".   It  may  be
78           more convenient when copying and pasting cross-references to manual
79           pages.  Note that the parentheses must normally be quoted  to  pro‐
80           tect them from the shell.)
81
82       man -a intro
83           Display,  in  succession,  all  of the available intro manual pages
84           contained within the manual.  It is possible to quit  between  suc‐
85           cessive displays or skip any of them.
86
87       man -t bash | lpr -Pps
88           Format  the  manual  page  for bash into the default troff or groff
89           format and pipe it to the printer named ps.  The default output for
90           groff  is usually PostScript.  man --help should advise as to which
91           processor is bound to the -t option.
92
93       man -l -Tdvi ./foo.1x.gz > ./foo.1x.dvi
94           This command will decompress and format  the  nroff  source  manual
95           page  ./foo.1x.gz  into a device independent (dvi) file.  The redi‐
96           rection is necessary as the -T flag causes output to be directed to
97           stdout  with  no  pager.  The output could be viewed with a program
98           such as xdvi or further processed into PostScript using  a  program
99           such as dvips.
100
101       man -k printf
102           Search the short descriptions and manual page names for the keyword
103           printf as regular expression.  Print out any  matches.   Equivalent
104           to apropos printf.
105
106       man -f smail
107           Lookup the manual pages referenced by smail and print out the short
108           descriptions of any found.  Equivalent to whatis smail.
109

OVERVIEW

111       Many options are available to man in order to give as much  flexibility
112       as  possible to the user.  Changes can be made to the search path, sec‐
113       tion order, output processor, and other behaviours and  operations  de‐
114       tailed below.
115
116       If set, various environment variables are interrogated to determine the
117       operation of man.  It is  possible  to  set  the  "catch-all"  variable
118       $MANOPT  to  any string in command line format, with the exception that
119       any spaces used as part of an option's argument must be  escaped  (pre‐
120       ceded by a backslash).  man will parse $MANOPT prior to parsing its own
121       command line.  Those options requiring an argument will  be  overridden
122       by the same options found on the command line.  To reset all of the op‐
123       tions set in $MANOPT, -D can be specified as the initial  command  line
124       option.  This will allow man to "forget" about the options specified in
125       $MANOPT, although they must still have been valid.
126
127       Manual pages are normally stored in nroff(1) format under  a  directory
128       such  as /usr/share/man.  In some installations, there may also be pre‐
129       formatted cat pages to improve performance.  See manpath(5) for details
130       of where these files are stored.
131
132       This package supports manual pages in multiple languages, controlled by
133       your locale.  If your system did not set this up for you automatically,
134       then  you may need to set $LC_MESSAGES, $LANG, or another system-depen‐
135       dent environment variable to indicate your  preferred  locale,  usually
136       specified in the POSIX format:
137
138       <language>[_<territory>[.<character-set>[,<version>]]]
139
140       If  the  desired page is available in your locale, it will be displayed
141       in lieu of the standard (usually American English) page.
142
143       If you find that the translations supplied with this  package  are  not
144       available  in  your  native language and you would like to supply them,
145       please contact the maintainer who will be coordinating such activity.
146
147       Individual manual pages are normally  written  and  maintained  by  the
148       maintainers  of  the  program, function, or other topic that they docu‐
149       ment, and are not included with this package.  If you find that a  man‐
150       ual  page is missing or inadequate, please report that to the maintain‐
151       ers of the package in question.
152
153       For information regarding other features and extensions available  with
154       this manual pager, please read the documents supplied with the package.
155

DEFAULTS

157       The  order  of  sections to search may be overridden by the environment
158       variable $MANSECT or by the SECTION directive in /etc/man_db.conf.   By
159       default it is as follows:
160
161              1 1p 8 2 3 3p 3pm 4 5 6 7 9 0p n l p o 1x 2x 3x 4x 5x 6x 7x 8x
162
163       The  formatted  manual  page  is  displayed using a pager.  This can be
164       specified in a number of ways, or else will fall back to a default (see
165       option -P for details).
166
167       The  filters are deciphered by a number of means.  Firstly, the command
168       line option -p or the environment variable $MANROFFSEQ is interrogated.
169       If  -p  was not used and the environment variable was not set, the ini‐
170       tial line of the nroff file is parsed for a  preprocessor  string.   To
171       contain a valid preprocessor string, the first line must resemble
172
173       '\" <string>
174
175       where  string  can be any combination of letters described by option -p
176       below.
177
178       If none of the above methods provide any filter information, a  default
179       set is used.
180
181       A  formatting  pipeline is formed from the filters and the primary for‐
182       matter (nroff or [tg]roff with -t) and executed.  Alternatively, if  an
183       executable program mandb_nfmt (or mandb_tfmt with -t) exists in the man
184       tree root, it is executed instead.  It gets passed  the  manual  source
185       file, the preprocessor string, and optionally the device specified with
186       -T or -E as arguments.
187

OPTIONS

189       Non-argument options that are duplicated either on the command line, in
190       $MANOPT,  or  both, are not harmful.  For options that require an argu‐
191       ment, each duplication will override the previous argument value.
192
193   General options
194       -C file, --config-file=file
195              Use this user configuration file  rather  than  the  default  of
196              ~/.manpath.
197
198       -d, --debug
199              Print debugging information.
200
201       -D, --default
202              This  option is normally issued as the very first option and re‐
203              sets man's behaviour to its default.  Its use is to reset  those
204              options  that  may  have  been set in $MANOPT.  Any options that
205              follow -D will have their usual effect.
206
207       --warnings[=warnings]
208              Enable warnings from groff.  This may be used to perform  sanity
209              checks on the source text of manual pages.  warnings is a comma-
210              separated list of warning names; if it is not supplied, the  de‐
211              fault  is  "mac".   See  the “Warnings” node in info groff for a
212              list of available warning names.
213
214   Main modes of operation
215       -f, --whatis
216              Equivalent to whatis.  Display a short description from the man‐
217              ual page, if available.  See whatis(1) for details.
218
219       -k, --apropos
220              Equivalent  to  apropos.   Search the short manual page descrip‐
221              tions for keywords and display any matches.  See apropos(1)  for
222              details.
223
224       -K, --global-apropos
225              Search  for  text  in  all  manual pages.  This is a brute-force
226              search, and is likely to take some time; if you can, you  should
227              specify  a section to reduce the number of pages that need to be
228              searched.  Search terms may be simple strings (the default),  or
229              regular expressions if the --regex option is used.
230
231              Note that this searches the sources of the manual pages, not the
232              rendered text, and so may include false positives due to  things
233              like  comments  in  source  files.   Searching the rendered text
234              would be much slower.
235
236       -l, --local-file
237              Activate "local" mode.  Format and display  local  manual  files
238              instead  of  searching  through  the system's manual collection.
239              Each manual page argument will be interpreted as an nroff source
240              file in the correct format.  No cat file is produced.  If '-' is
241              listed as one of the arguments, input will be taken from  stdin.
242              When this option is not used, and man fails to find the page re‐
243              quired, before displaying the error message, it attempts to  act
244              as if this option was supplied, using the name as a filename and
245              looking for an exact match.
246
247       -w, --where, --path, --location
248              Don't actually display the manual page, but do print  the  loca‐
249              tion  of  the source nroff file that would be formatted.  If the
250              -a option is also used, then print the locations of  all  source
251              files that match the search criteria.
252
253       -W, --where-cat, --location-cat
254              Don't  actually  display the manual page, but do print the loca‐
255              tion of the preformatted cat file that would be  displayed.   If
256              the -a option is also used, then print the locations of all pre‐
257              formatted cat files that match the search criteria.
258
259              If -w and -W are both used, then print both source file and  cat
260              file  separated  by a space.  If all of -w, -W, and -a are used,
261              then do this for each possible match.
262
263       -c, --catman
264              This option is not for general use and should only  be  used  by
265              the catman program.
266
267       -R encoding, --recode=encoding
268              Instead  of  formatting the manual page in the usual way, output
269              its source converted to the specified encoding.  If you  already
270              know  the  encoding  of  the  source file, you can also use man‐
271              conv(1) directly.  However, this option allows  you  to  convert
272              several  manual pages to a single encoding without having to ex‐
273              plicitly state the encoding of each, provided that they were al‐
274              ready  installed in a structure similar to a manual page hierar‐
275              chy.
276
277              Consider using man-recode(1)  instead  for  converting  multiple
278              manual  pages,  since it has an interface designed for bulk con‐
279              version and so can be much faster.
280
281   Finding manual pages
282       -L locale, --locale=locale
283              man will normally determine your current locale by a call to the
284              C  function  setlocale(3) which interrogates various environment
285              variables, possibly including $LC_MESSAGES and $LANG.  To tempo‐
286              rarily  override the determined value, use this option to supply
287              a locale string directly to man.  Note that it will not take ef‐
288              fect until the search for pages actually begins.  Output such as
289              the help message will always be displayed in the  initially  de‐
290              termined locale.
291
292       -m system[,...], --systems=system[,...]
293              If  this  system  has  access to other operating systems' manual
294              pages, they can be accessed using this option.  To search for  a
295              manual  page from NewOS's manual page collection, use the option
296              -m NewOS.
297
298              The system specified can be a combination of comma delimited op‐
299              erating system names.  To include a search of the native operat‐
300              ing system's manual pages, include the system name  man  in  the
301              argument string.  This option will override the $SYSTEM environ‐
302              ment variable.
303
304       -M path, --manpath=path
305              Specify an alternate manpath to use.  By default, man uses  man‐
306              path  derived code to determine the path to search.  This option
307              overrides the $MANPATH environment variable and causes option -m
308              to be ignored.
309
310              A  path specified as a manpath must be the root of a manual page
311              hierarchy structured into sections as described  in  the  man-db
312              manual  (under  "The manual page system").  To view manual pages
313              outside such hierarchies, see the -l option.
314
315       -S list, -s list, --sections=list
316              The given list is a colon- or comma-separated list of  sections,
317              used  to  determine  which manual sections to search and in what
318              order.  This option overrides the $MANSECT environment variable.
319              (The -s spelling is for compatibility with System V.)
320
321       -e sub-extension, --extension=sub-extension
322              Some systems incorporate large packages of manual pages, such as
323              those that accompany the Tcl package, into the main manual  page
324              hierarchy.  To get around the problem of having two manual pages
325              with the same name such as exit(3), the Tcl pages  were  usually
326              all  assigned  to  section l.  As this is unfortunate, it is now
327              possible to put the pages in the correct section, and to  assign
328              a specific "extension" to them, in this case, exit(3tcl).  Under
329              normal operation, man will  display  exit(3)  in  preference  to
330              exit(3tcl).   To negotiate this situation and to avoid having to
331              know which section the page you require resides in,  it  is  now
332              possible  to  give  man  a sub-extension string indicating which
333              package the page must belong to.  Using the above example,  sup‐
334              plying  the  option  -e tcl  to  man will restrict the search to
335              pages having an extension of *tcl.
336
337       -i, --ignore-case
338              Ignore case when searching for manual pages.  This  is  the  de‐
339              fault.
340
341       -I, --match-case
342              Search for manual pages case-sensitively.
343
344       --regex
345              Show  all pages with any part of either their names or their de‐
346              scriptions matching each page argument as a regular  expression,
347              as with apropos(1).  Since there is usually no reasonable way to
348              pick a "best" page when searching for a regular expression, this
349              option implies -a.
350
351       --wildcard
352              Show  all pages with any part of either their names or their de‐
353              scriptions matching each page argument using  shell-style  wild‐
354              cards,  as  with  apropos(1) --wildcard.  The page argument must
355              match the entire name or description, or match  on  word  bound‐
356              aries  in the description.  Since there is usually no reasonable
357              way to pick a "best" page when searching for  a  wildcard,  this
358              option implies -a.
359
360       --names-only
361              If  the  --regex  or  --wildcard option is used, match only page
362              names, not page descriptions, as with whatis(1).  Otherwise,  no
363              effect.
364
365       -a, --all
366              By  default,  man  will  exit after displaying the most suitable
367              manual page it finds.  Using this option forces man  to  display
368              all the manual pages with names that match the search criteria.
369
370       -u, --update
371              This  option  causes  man  to  update its database caches of in‐
372              stalled manual pages.  This is only needed in  rare  situations,
373              and it is normally better to run mandb(8) instead.
374
375       --no-subpages
376              By default, man will try to interpret pairs of manual page names
377              given on the command line as equivalent to a single manual  page
378              name  containing  a  hyphen or an underscore.  This supports the
379              common pattern of programs that implement a  number  of  subcom‐
380              mands,  allowing  them to provide manual pages for each that can
381              be accessed using similar syntax as would be used to invoke  the
382              subcommands themselves.  For example:
383
384                $ man -aw git diff
385                /usr/share/man/man1/git-diff.1.gz
386
387              To disable this behaviour, use the --no-subpages option.
388
389                $ man -aw --no-subpages git diff
390                /usr/share/man/man1/git.1.gz
391                /usr/share/man/man3/Git.3pm.gz
392                /usr/share/man/man1/diff.1.gz
393
394   Controlling formatted output
395       -P pager, --pager=pager
396              Specify  which  output pager to use.  By default, man uses less,
397              falling back to cat if less is not found or is  not  executable.
398              This  option overrides the $MANPAGER environment variable, which
399              in turn overrides the $PAGER environment variable.   It  is  not
400              used in conjunction with -f or -k.
401
402              The  value  may be a simple command name or a command with argu‐
403              ments, and may use shell quoting (backslashes, single quotes, or
404              double  quotes).   It may not use pipes to connect multiple com‐
405              mands; if you need that, use a wrapper script,  which  may  take
406              the file to display either as an argument or on standard input.
407
408       -r prompt, --prompt=prompt
409              If  a  recent version of less is used as the pager, man will at‐
410              tempt to set its prompt and some sensible options.  The  default
411              prompt looks like
412
413               Manual page name(sec) line x
414
415              where name denotes the manual page name, sec denotes the section
416              it was found under and x  the  current  line  number.   This  is
417              achieved by using the $LESS environment variable.
418
419              Supplying  -r  with  a  string  will override this default.  The
420              string may contain the text $MAN_PN which will  be  expanded  to
421              the  name  of  the current manual page and its section name sur‐
422              rounded by "(" and ")".  The string used to produce the  default
423              could be expressed as
424
425              \ Manual\ page\ \$MAN_PN\ ?ltline\ %lt?L/%L.:
426              byte\ %bB?s/%s..?\ (END):?pB\ %pB\\%..
427              (press h for help or q to quit)
428
429              It  is  broken into three lines here for the sake of readability
430              only.  For its meaning see the less(1) manual page.  The  prompt
431              string  is  first  evaluated  by  the shell.  All double quotes,
432              back-quotes and backslashes in the prompt must be escaped  by  a
433              preceding  backslash.  The prompt string may end in an escaped $
434              which may be followed by further options for less.   By  default
435              man sets the -ix8 options.
436
437              The $MANLESS environment variable described below may be used to
438              set a default prompt string if none is supplied on  the  command
439              line.
440
441       -7, --ascii
442              When  viewing a pure ascii(7) manual page on a 7 bit terminal or
443              terminal emulator, some characters  may  not  display  correctly
444              when  using  the  latin1(7)  device  description with GNU nroff.
445              This option allows pure ascii manual pages to  be  displayed  in
446              ascii  with the latin1 device.  It will not translate any latin1
447              text.  The following table  shows  the  translations  performed:
448              some  parts  of it may only be displayed properly when using GNU
449              nroff's latin1(7) device.
450
451
452              Description        Octal   latin1   ascii
453              ──────────────────────────────────────────
454              continuation hy‐    255      ‐        -
455              phen
456              bullet (middle      267      •        o
457              dot)
458              acute accent        264      ´        '
459              multiplication      327      ×        x
460              sign
461
462              If  the  latin1  column displays correctly, your terminal may be
463              set up for latin1 characters and this option is  not  necessary.
464              If  the  latin1 and ascii columns are identical, you are reading
465              this page using this option or man did not format this page  us‐
466              ing  the  latin1  device  description.   If the latin1 column is
467              missing or corrupt, you may need to view manual pages with  this
468              option.
469
470              This  option is ignored when using options -t, -H, -T, or -Z and
471              may be useless for nroff other than GNU's.
472
473       -E encoding, --encoding=encoding
474              Generate output for a character encoding other than the default.
475              For backward compatibility, encoding may be an nroff device such
476              as ascii, latin1, or utf8 as well as a true  character  encoding
477              such as UTF-8.
478
479       --no-hyphenation, --nh
480              Normally, nroff will automatically hyphenate text at line breaks
481              even in words that do not contain hyphens, if it is necessary to
482              do  so  to  lay  out  words on a line without excessive spacing.
483              This option disables automatic hyphenation, so words  will  only
484              be hyphenated if they already contain hyphens.
485
486              If  you  are  writing  a  manual page and simply want to prevent
487              nroff from hyphenating a word at an inappropriate point, do  not
488              use  this  option,  but consult the nroff documentation instead;
489              for instance, you can put "\%" inside a word to indicate that it
490              may  be  hyphenated at that point, or put "\%" at the start of a
491              word to prevent it from being hyphenated.
492
493       --no-justification, --nj
494              Normally, nroff will automatically justify text to both margins.
495              This  option disables full justification, leaving justified only
496              to the left margin, sometimes called "ragged-right" text.
497
498              If you are writing a manual page  and  simply  want  to  prevent
499              nroff  from  justifying  certain paragraphs, do not use this op‐
500              tion, but consult the nroff documentation instead; for instance,
501              you  can use the ".na", ".nf", ".fi", and ".ad" requests to tem‐
502              porarily disable adjusting and filling.
503
504       -p string, --preprocessor=string
505              Specify the sequence of preprocessors to  run  before  nroff  or
506              troff/groff.  Not all installations will have a full set of pre‐
507              processors.  Some of the preprocessors and the letters  used  to
508              designate  them are: eqn (e), grap (g), pic (p), tbl (t), vgrind
509              (v), refer (r).  This option overrides the $MANROFFSEQ  environ‐
510              ment  variable.   zsoelim  is  always run as the very first pre‐
511              processor.
512
513       -t, --troff
514              Use groff -mandoc to format the manual page to stdout.  This op‐
515              tion is not required in conjunction with -H, -T, or -Z.
516
517       -T[device], --troff-device[=device]
518              This option is used to change groff (or possibly troff's) output
519              to be suitable for a device other than the default.  It  implies
520              -t.   Examples  (provided  with Groff-1.17) include dvi, latin1,
521              ps, utf8, X75 and X100.
522
523       -H[browser], --html[=browser]
524              This option will cause groff to produce HTML  output,  and  will
525              display  that output in a web browser.  The choice of browser is
526              determined by the optional browser argument if one is  provided,
527              by  the  $BROWSER environment variable, or by a compile-time de‐
528              fault if that is unset (usually lynx).  This option implies  -t,
529              and will only work with GNU troff.
530
531       -X[dpi], --gxditview[=dpi]
532              This  option  displays the output of groff in a graphical window
533              using the gxditview program.  The dpi (dots per inch) may be 75,
534              75-12,  100, or 100-12, defaulting to 75; the -12 variants use a
535              12-point base font.   This  option  implies  -T  with  the  X75,
536              X75-12, X100, or X100-12 device respectively.
537
538       -Z, --ditroff
539              groff  will run troff and then use an appropriate post-processor
540              to produce output suitable for  the  chosen  device.   If  groff
541              -mandoc  is  groff, this option is passed to groff and will sup‐
542              press the use of a post-processor.  It implies -t.
543
544   Getting help
545       -?, --help
546              Print a help message and exit.
547
548       --usage
549              Print a short usage message and exit.
550
551       -V, --version
552              Display version information.
553

EXIT STATUS

555       0      Successful program execution.
556
557       1      Usage, syntax or configuration file error.
558
559       2      Operational error.
560
561       3      A child process returned a non-zero exit status.
562
563       16     At least one of the pages/files/keywords didn't exist or  wasn't
564              matched.
565

ENVIRONMENT

567       MANPATH
568              If  $MANPATH is set, its value is used as the path to search for
569              manual pages.
570
571              See the SEARCH PATH section of manpath(5) for the default behav‐
572              iour and details of how this environment variable is handled.
573
574       MANROFFOPT
575              Every  time  man invokes the formatter (nroff, troff, or groff),
576              it adds the contents of $MANROFFOPT to the  formatter's  command
577              line.
578
579       MANROFFSEQ
580              If $MANROFFSEQ is set, its value is used to determine the set of
581              preprocessors to pass each manual  page  through.   The  default
582              preprocessor list is system dependent.
583
584       MANSECT
585              If  $MANSECT is set, its value is a colon-delimited list of sec‐
586              tions and it is used  to  determine  which  manual  sections  to
587              search and in what order.  The default is "1 1p 8 2 3 3p 3pm 4 5
588              6 7 9 0p n l p o 1x 2x 3x 4x 5x 6x 7x 8x", unless overridden  by
589              the SECTION directive in /etc/man_db.conf.
590
591       MANPAGER, PAGER
592              If $MANPAGER or $PAGER is set ($MANPAGER is used in preference),
593              its value is used as the name of the program used to display the
594              manual  page.   By default, less is used, falling back to cat if
595              less is not found or is not executable.
596
597              The value may be a simple command name or a command  with  argu‐
598              ments, and may use shell quoting (backslashes, single quotes, or
599              double quotes).  It may not use pipes to connect  multiple  com‐
600              mands;  if  you  need that, use a wrapper script, which may take
601              the file to display either as an argument or on standard input.
602
603       MANLESS
604              If $MANLESS is set, its value will be used as the default prompt
605              string for the less pager, as if it had been passed using the -r
606              option (so any occurrences of the text $MAN_PN will be  expanded
607              in  the  same  way).  For example, if you want to set the prompt
608              string unconditionally to “my prompt string”,  set  $MANLESS  to
609-Psmy prompt string’.  Using the -r option overrides this envi‐
610              ronment variable.
611
612       BROWSER
613              If $BROWSER is set, its value is a colon-delimited list of  com‐
614              mands,  each  of  which  in  turn  is used to try to start a web
615              browser for man --html.  In each command, %s is  replaced  by  a
616              filename  containing  the HTML output from groff, %% is replaced
617              by a single percent sign (%), and %c is replaced by a colon (:).
618
619       SYSTEM If $SYSTEM is set, it will have the same effect  as  if  it  had
620              been specified as the argument to the -m option.
621
622       MANOPT If $MANOPT is set, it will be parsed prior to man's command line
623              and is expected to be in a similar format.  As all of the  other
624              man  specific  environment variables can be expressed as command
625              line options, and are thus  candidates  for  being  included  in
626              $MANOPT  it  is  expected  that they will become obsolete.  N.B.
627              All spaces that should be interpreted as part of an option's ar‐
628              gument must be escaped.
629
630       MANWIDTH
631              If  $MANWIDTH  is  set, its value is used as the line length for
632              which manual pages should be formatted.  If it is not set,  man‐
633              ual  pages  will  be formatted with a line length appropriate to
634              the current terminal (using the value of $COLUMNS, and  ioctl(2)
635              if  available,  or  falling  back to 80 characters if neither is
636              available).  Cat pages will only be saved when the default  for‐
637              matting  can  be  used, that is when the terminal line length is
638              between 66 and 80 characters.
639
640       MAN_KEEP_FORMATTING
641              Normally, when output is not being directed to a terminal  (such
642              as  to a file or a pipe), formatting characters are discarded to
643              make it easier to read the result without special  tools.   How‐
644              ever,  if  $MAN_KEEP_FORMATTING  is  set to any non-empty value,
645              these formatting characters are retained.  This  may  be  useful
646              for  wrappers  around  man that can interpret formatting charac‐
647              ters.
648
649       MAN_KEEP_STDERR
650              Normally, when output is being directed to a  terminal  (usually
651              to  a  pager), any error output from the command used to produce
652              formatted versions of manual pages is discarded to avoid  inter‐
653              fering  with  the pager's display.  Programs such as groff often
654              produce relatively  minor  error  messages  about  typographical
655              problems  such as poor alignment, which are unsightly and gener‐
656              ally confusing when displayed along with the manual page.   How‐
657              ever,   some   users   want   to   see   them   anyway,  so,  if
658              $MAN_KEEP_STDERR is set to any  non-empty  value,  error  output
659              will be displayed as usual.
660
661       MAN_DISABLE_SECCOMP
662              On  Linux,  man  normally  confines subprocesses that handle un‐
663              trusted data using a seccomp(2) sandbox.  This makes it safer to
664              run  complex  parsing code over arbitrary manual pages.  If this
665              goes wrong for some reason unrelated to the content of the  page
666              being  displayed,  you  can set $MAN_DISABLE_SECCOMP to any non-
667              empty value to disable the sandbox.
668
669       PIPELINE_DEBUG
670              If the $PIPELINE_DEBUG environment variable is set to "1",  then
671              man  will  print debugging messages to standard error describing
672              each subprocess it runs.
673
674       LANG, LC_MESSAGES
675              Depending on system and implementation, either or both of  $LANG
676              and  $LC_MESSAGES  will  be interrogated for the current message
677              locale.  man will display its messages in that locale (if avail‐
678              able).  See setlocale(3) for precise details.
679

FILES

681       /etc/man_db.conf
682              man-db configuration file.
683
684       /usr/share/man
685              A global manual page hierarchy.
686

SEE ALSO

688       apropos(1),   groff(1),   less(1),   manpath(1),   nroff(1),  troff(1),
689       whatis(1), zsoelim(1), manpath(5), man(7), catman(8), mandb(8)
690
691       Documentation for some packages may be available in other formats, such
692       as info(1) or HTML.
693

HISTORY

695       1990, 1991 – Originally written by John W. Eaton (jwe@che.utexas.edu).
696
697       Dec 23 1992: Rik Faith (faith@cs.unc.edu) applied bug fixes supplied by
698       Willem Kasdorp (wkasdo@nikhefk.nikef.nl).
699
700       30th April 1994 – 23rd February 2000: Wilf. (G.Wilford@ee.surrey.ac.uk)
701       has been developing and maintaining this package with the help of a few
702       dedicated people.
703
704       30th October 1996 – 30th March  2001:  Fabrizio  Polacco  <fpolacco@de‐
705       bian.org>  maintained and enhanced this package for the Debian project,
706       with the help of all the community.
707
708       31st March 2001 – present day: Colin  Watson  <cjwatson@debian.org>  is
709       now developing and maintaining man-db.
710

BUGS

712       https://gitlab.com/cjwatson/man-db/-/issues
713       https://savannah.nongnu.org/bugs/?group=man-db
714
715
716
7172.10.2                            2022-03-17                            MAN(1)
Impressum