mjhjmtu

Why would a specific man page (in my case, for the nc command) have today's date without me doing any updates to the system ? Also, why doesn't the "unattended update" log show any specific activity for that day?

2018-03-14 07:47:38,124 INFO Initial blacklisted packages:
2018-03-14 07:47:38,135 INFO Starting unattended upgrades script
2018-03-14 07:47:38,135 INFO Allowed origins are: ['o=LinuxMint,a=qiana-security', 'o=LinuxMintESM,a=qiana']
2018-03-14 07:47:51,767 INFO No packages found that can be upgraded unattended and no pending auto-removals

This is footer for the nc man page:

BSD March 14, 2018 BSD

That's on Linux Mint 17 (qiana), based on Ubuntu 14.04 (trusty) with groff 1.22.2 and man-db 2.6.7.1.

EDIT

Requested commands outputs :

1. 
   

   man -aw nc

   
   
   

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

   
   


2. 
   

   ls -ld $(man -aw nc)

   
   
   

   -rw-r--r-- 1 root root 5.7K Dec 4 2012 /usr/share/man/man1/nc_openbsd.1.gz
   

   
   

Which is weird...

3. 
   

   dpkg -S $(man -aw nc)?

   
   
   

   netcat-openbsd: /usr/share/man/man1/nc_openbsd.1.gz
   

   
   


4. 
   

   type -a man

   
   
   

   man is /usr/bin/man
   

   
   


5. 
   

   zgrep docdate $(man -aw nc)

   
   
   

   .Dd $Mdocdate: February 7 2012 $
   

   
   


6. 
   

   ADDED FOOTER strace -f man nc 2>&1 | grep -e '^BSD' -e '"/.*nc'

   
   
   

   ychaouche#ychaouche-PC 14:31:15 ~ $ strace -f man nc 2>&1 | grep -e '^BSD' -e '"/.*nc'
   execve("/usr/bin/man", ["man", "nc"], [/* 87 vars */]) = 0
   lstat("/usr/share/man/man1/nc.1.gz", st_mode=S_IFLNK) = 0
   lstat("/usr/share/man/man1/nc.1.gz", st_mode=S_IFLNK) = 0
   readlink("/usr/share/man/man1/nc.1.gz", "/etc/alternatives/nc.1.gz", 4095) = 25
   lstat("/etc/alternatives/nc.1.gz", st_mode=S_IFLNK) = 0
   readlink("/etc/alternatives/nc.1.gz", "/usr/share/man/man1/nc_openbsd.1"..., 4095) = 35
   lstat("/usr/share/man/man1/nc_openbsd.1.gz", 0644, st_size=5756, ...) = 0
   stat("/usr/share/man/man1/nc_openbsd.1.gz", 0644, st_size=5756, ...) = 0
   stat("/usr/share/man/man1/nc_openbsd.1.gz", 0644, st_size=5756, ...) = 0
   open("/usr/share/man/man1/nc_openbsd.1.gz", O_RDONLY) = 3
   access("/usr/share/man/man1/nc.1.gz", R_OK) = 0
   lstat("/usr/share/man/man1/nc.1.gz", st_mode=S_IFLNK) = 0
   lstat("/usr/share/man/man1/nc.1.gz", st_mode=S_IFLNK) = 0
   readlink("/usr/share/man/man1/nc.1.gz", "/etc/alternatives/nc.1.gz", 4095) = 25
   lstat("/etc/alternatives/nc.1.gz", st_mode=S_IFLNK) = 0
   readlink("/etc/alternatives/nc.1.gz", "/usr/share/man/man1/nc_openbsd.1"..., 4095) = 35
   lstat("/usr/share/man/man1/nc_openbsd.1.gz", 0644, st_size=5756, ...) = 0
   stat("/usr/share/man/man1/nc_openbsd.1.gz", 0644, st_size=5756, ...) = 0
   stat("/usr/share/man/man1/nc_openbsd.1.gz", 0644, st_size=5756, ...) = 0
   open("/usr/share/man/man1/nc_openbsd.1.gz", O_RDONLY) = 3
   stat("/usr/share/man/man1/nc.1.gz", 0644, st_size=5756, ...) = 0
   stat("/usr/share/man/cat1/nc.1.gz", 0x7fffa49c0940) = -1 ENOENT (No such file or directory)
   stat("/usr/share/man/man1/nc_openbsd.1.gz", 0644, st_size=5756, ...) = 0
   open("/usr/share/man/man1/nc_openbsd.1.gz", O_RDONLY) = 3
   [pid 3878] stat("/usr/share/man/man1/nc_openbsd.1.gz", 0644, st_size=5756, ...) = 0
   [pid 3878] access("/usr/share/man/man1/nc_openbsd.1.gz", R_OK <unfinished ...>
   BSD March 20, 2018 BSD
   

   
   


7. 
   

   strace -f man nc 2>&1 | grep -vwe -1 | grep -o '"/[^"]*"' | sort -u | grep -v /dev/ | xargs sh -c 'zgrep "March 14" "$@"' sh 2> /dev/null

   
   
   

    no output
   

   
   
   

   it seems the date isn't hardcoded. Could be a macro generating today's date.

   
   


8. 
   

   env | grep -e ROFF -e MAN -e GRO

   
   
   

   SESSION_MANAGER=local/ychaouche-PC:@/tmp/.ICE-unix/2915,unix/ychaouche-PC:/tmp/.ICE-unix/2915
   MANDATORY_PATH=/usr/share/gconf/default.mandatory.path
   

   
   



9. env -i man nc shows today's date (March 20th 2018)



10. 
    

    zcat /usr/share/man/man1/nc_openbsd.1.gz | nroff -mandoc | grep BSD

    
    
    

    ychaouche#ychaouche-PC 06:59:53 ~ $ zcat /usr/share/man/man1/nc_openbsd.1.gz | nroff -mandoc | grep BSD
    NC(1) BSD General Commands Manual NC(1)
    BSD March 20, 2018 BSD
    ychaouche#ychaouche-PC 07:01:41 ~ $
    

    
    


11. 
    

    strace -f man nc 2>&1 | grep -vwe -1 | grep -o '"/[^"]*tmac/[^"]*"' | sort -u | xargs ls -lrtd

    
    
    

    ychaouche#ychaouche-PC 17:26:08 /usr/share/man/man1 $ unalias ls
    ychaouche#ychaouche-PC 17:26:12 /usr/share/man/man1 $ unalias xargs
    ychaouche#ychaouche-PC 17:26:14 /usr/share/man/man1 $ unalias grep
    ychaouche#ychaouche-PC 17:26:16 /usr/share/man/man1 $ strace -f man nc 2>&1 | grep -vwe -1 | grep -o '"/[^"]*tmac/[^"]*"' | sort -u | xargs ls -lrtd
    -rw-r--r-- 1 root root 4065 Jan 22 2014 /usr/share/groff/1.22.2/tmac/papersize.tmac
    -rw-r--r-- 1 root root 1860 Jan 22 2014 /usr/share/groff/1.22.2/tmac/andoc.tmac
    -rw-r--r-- 1 root root 71 Jan 22 2014 /usr/share/groff/1.22.2/tmac/unicode.tmac
    -rw-r--r-- 1 root root 1552 Jan 22 2014 /usr/share/groff/1.22.2/tmac/tty.tmac
    -rw-r--r-- 1 root root 5183 Jan 22 2014 /usr/share/groff/1.22.2/tmac/tty-char.tmac
    -rw-r--r-- 1 root root 1145 Jan 22 2014 /usr/share/groff/1.22.2/tmac/troffrc-end
    -rw-r--r-- 1 root root 1387 Jan 22 2014 /usr/share/groff/1.22.2/tmac/troffrc
    -rw-r--r-- 1 root root 4729 Jan 22 2014 /usr/share/groff/1.22.2/tmac/pspic.tmac
    -rw-r--r-- 1 root root 22042 Jan 22 2014 /usr/share/groff/1.22.2/tmac/mdoc/doc-syms
    -rw-r--r-- 1 root root 4048 Jan 22 2014 /usr/share/groff/1.22.2/tmac/mdoc/doc-nroff
    -rw-r--r-- 1 root root 29284 Jan 22 2014 /usr/share/groff/1.22.2/tmac/mdoc/doc-common
    -rw-r--r-- 1 root root 2250 Jan 22 2014 /usr/share/groff/1.22.2/tmac/latin1.tmac
    -rw-r--r-- 1 root root 27860 Jan 22 2014 /usr/share/groff/1.22.2/tmac/hyphen.us
    -rw-r--r-- 1 root root 15678 Jan 22 2014 /usr/share/groff/1.22.2/tmac/hyphenex.us
    -rw-r--r-- 1 root root 1362 Jan 22 2014 /usr/share/groff/1.22.2/tmac/fallbacks.tmac
    -rw-r--r-- 1 root root 73807 Jan 22 2014 /usr/share/groff/1.22.2/tmac/doc.tmac
    -rw-r--r-- 1 root root 537 Jan 22 2014 /usr/share/groff/1.22.2/tmac/composite.tmac
    -rw-r--r-- 1 root root 704 Jan 22 2014 /usr/share/groff/site-tmac/mdoc.local
    ychaouche#ychaouche-PC 17:26:18 /usr/share/man/man1 $
    

    
    

GNU roff used not to support those:

 .Dd $Mdocdate: February 7 2012 $

OpenBSD extension (here that $Mdocdate: ...$ being a CVS/RCS keyword expanded by CVS (which OpenBSD uses to version control their code) with the date of the manual revision), resulting in the current date to be expanded instead of the one specified. I can reproduce it on Ubuntu 14.04 for all man pages that have such a Mdocdate.

See https://savannah.gnu.org/bugs/?42968 implemented in https://lists.gnu.org/archive/html/groff-commit/2014-10/msg00092.html (groff version 1.22.3).

For man pages from MirBSD (now MirOS) like your paxcpio or mksh, which use the same $Mdocdate: ...$ CVS keyword, you'll find the man pages redefine (wrap) the .Dd mdoc macro themselves, so the roff system macros don't have to support it:

."
." Implement .Dd with the Mdocdate RCS keyword
."
.rn Dd xD
.de Dd
.ie ^G\$1^G$Mdocdate:^G 
. xD \$2 \$3, \$4
.
.el .xD \$1 \$2 \$3 \$4 \$5 \$6 \$7 \$8
..
."
." .Dd must come before definition of .Mx, because when called
." with -mandoc, it might implement .Mx itself, but we want to
." use our own definition. And .Dd must come *first*, always.
."
.Dd $Mdocdate: August 16 2017 $