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Topic: FreeBSD on MacOS |
Jeff Hyman
From:
West Virginia, USA
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Posted 10 Oct 2008 3:55 pm |
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| Anyone have a new Mac? I here they are running BSD behind the scenes. If true, has anyone gone to the shell and explored? |
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Michael Maddex
From:
Northern New Mexico, USA
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Posted 11 Oct 2008 4:41 pm
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Since nobody else has jumped in here, I'll try and answer your question. I came to OS X from Linux/BSD a few years ago out of curiosity and only use it once in awhile, so I'm no expert.
SYSTEM: From the beginning, Mac OS X has been built on BSD among other components. In a nutshell, at the bottom of the OS stack is Darwin, composed of BSD code and the Mach kernel from CMU. Both are free software. A pair of graphics engines rides on top of that, one Mac proprietary and one free software, OpenGL. Aqua is the GUI and sits on top of the OS stack. There are of course other components: file system, TCP/IP and so on, but that's the basic setup.
UNIX: Unfortunately, much of the functionality of the <tt>/etc/</tt> files has been transferred to a registry-like database, Netinfo. Although you'll find <tt>/etc/hosts, /etc/passwd</tt>, etc., the system doesn't read them, it reads Netinfo. As an administrator, you can edit the db with Netinfo Manager. You can get a terminal window in the GUI to explore the file system. All of the usual shell commands work. I believe that the default shell is <tt>csh</tt>. I changed mine to <tt>bash</tt> (10.2 and later) in Netinfo, not <tt>/etc/passwd</tt>.
RESOURCES: I believe that O'Reilly publishes a book called OS X for Unix Users or something similar. I haven't seen a copy. The Missing Manual: OS X by David Pogue is pretty good. I have an early edition (10.1) with a lot of typos and a few downright errors, but the newer editions seem to have fixed that. There have been editions to match each release (10.x). Building Cocoa Applications, also from O'Reilly, is a good introduction to OS X programming which uses Objective C. The projects in the book are non-trivial and the authors assume prior programming experience in C or C++.
I could go on, but this is getting kind of long. I'm really a Slackware kind of guy, OS X is just a sideline for me, but I'll be glad to try and answer any questions you have.
HTH.
_________________
"For every expert, there is an equal and opposite expert." -- Arthur C. Clarke |
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b0b
From:
Cloverdale, CA, USA
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Posted 11 Oct 2008 9:23 pm
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Michael obviously knows the nuts and bolts better than me. I'm not a Unix power user, but I'm not scared of it either.
There are a few oddities when you open the shell. You can't login as root. If you want to do something with root access, you have to preface it with <code>sudo</code>.
Filenames aren't case sensitive. That really threw me when I encountered it.
It doesn't use the FreeBSD distribution/update system (I forget what that was called. RPM, maybe?). Thank goodness! That thing is really awkward. Apple has its own Software Update program that's very user-friendly.
_________________
-πππ- (admin) - Robert P. Lee - Recordings - Breathe - D6th - Video |
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Jeff Hyman
From:
West Virginia, USA
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Posted 12 Oct 2008 12:07 am
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Michael,
I've gotten very use to bash, and prefer it over csh...but my real comfort level is in the korn shell (ksh). /etc/passwd... so it exists and is not used? is that correct? Does the Netinfo deal with /etc/passwd at any level behind the scenes? I guess I'm trying to figure out why Mac would even put /etc/passwd on the system at all. Is there a /tcb directory? BTW: You have more knowledge then you take credit for :-)
Bob,
Case insensitive! Wow. What about blank spaces in a file or dir name? That's to much like windoze for me <g>. Sounds like grep doesn't need the -i or -y flag.
With all the good feedback, let me ask:
# file <compiled_filename>
What does it return?
# tar -?
How does 'tar' function?
The su command is actually a good thing. Using su to get a root login is common on many Unix OS's. My first experience with this was the DEC Alpha. It didn't make sense back in those days... but with all the security issues it's actually one more level a hacker needs to get past.
Anyway... I want to leap into the backup and crash recovery side of the MacOS. If 'tar' or even 'cpio' work from the shell will certainly be good news for me. |
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Randy Phelps
From:
California, USA
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Posted 12 Oct 2008 7:53 pm
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Netinfo has been discontinued if you have later versions of the OS. OpenDirectory is now what is used and with a little time I think you'll find that if you are a unix guy you'll find it is a sterling unix.
it is trivial to cease using the gui if that is your choice, I'd also recommend installing and enabling x11.
There are several good unix boards on the apple support site... and some good links at slashdot...
I've been a user of what became OSX since late 98.. I dig it and it keeps getting better... but I am biased! |
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Jeff Hyman
From:
West Virginia, USA
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Posted 13 Oct 2008 12:37 am
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Randy,
Thanks for the reply. Do you keep any valuable files on your Mac? Whats your backup method and utility?
I'm digging to see how data is stored and recovered. 4mm? USB? SCSI? ftp? ssh? Samba? NAS?
To this day, I stay at the command prompt. GUI has never been my choice. Correct me if I'm wrong, but if I jump into the Mac world, I better get use to GUI? ... or at the SysAdmin level it's acceptable to do chores at the command prompt? How would a simple character based interface be received. Easy to use, would include source.
I forgot that the Unix community has a large wealth of musicians. Seems programmers and music fit well. I can remember back in the 80's at the SCO Forums in Santa Cruz. Lots of entertainment from attendees and exibitors. |
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Brad Bechtel
From:
San Francisco, CA
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Jeff Hyman
From:
West Virginia, USA
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Posted 13 Oct 2008 11:03 am
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Brad,
Thanks for the links. The developers program is exactly where I'm heading. Do you personally get into any low-level code there? |
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John Cipriano
From:
San Francisco
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Posted 17 Oct 2008 8:03 pm
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Jeff, tar and file work from the terminal. Tar is the GNU version, I don't know about file. cpio is there as well. Most of the day to day *nix stuff is there.
I think they have actually gone back to using /etc/hosts in Leopard. At least, that's where I add my hosts, and they work.
You can get a lot of what's missing from a traditional Unix (like X server) via MacPorts or something similar. |
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Jeff Hyman
From:
West Virginia, USA
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Posted 20 Oct 2008 3:36 pm
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John,
Thanks for the reply and info. I'm still gathering details. If you get a chance, what is the output of:
# file <compiled_filename>
What does it return?
# tar -?
How does 'tar' function? |
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b0b
From:
Cloverdale, CA, USA
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Posted 20 Oct 2008 4:02 pm
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| Code: |
bob-lees-mac-pro:~ b0bMini$ file <compiled_filename>
-bash: syntax error near unexpected token `newline'
bob-lees-mac-pro:~ b0bMini$ tar -?
Usage: tar [OPTION...] [FILE]...
GNU `tar' saves many files together into a single tape or disk archive, and can
restore individual files from the archive.
Examples:
tar -cf archive.tar foo bar # Create archive.tar from files foo and bar.
tar -tvf archive.tar # List all files in archive.tar verbosely.
tar -xf archive.tar # Extract all files from archive.tar.
Main operation mode:
-A, --catenate, --concatenate append tar files to an archive
-c, --create create a new archive
-d, --diff, --compare find differences between archive and file system
--delete delete from the archive (not on mag tapes!)
-r, --append append files to the end of an archive
-t, --list list the contents of an archive
-u, --update only append files newer than copy in archive
-x, --extract, --get extract files from an archive
Operation modifiers:
-g, --listed-incremental=FILE handle new GNU-format incremental backup
-G, --incremental handle old GNU-format incremental backup
--ignore-failed-read do not exit with nonzero on unreadable files
-k, --keep-old-files don't replace existing files when extracting
--keep-newer-files don't replace existing files that are newer than
their archive copies
--no-overwrite-dir preserve metadata of existing directories
-n, --seek Archive is seekable
--occurrence[=NUMBER] process only the NUMth occurrence of each file in
the archive. This option is valid only in
conjunction with one of the subcommands --delete,
--diff, --extract or --list and when a list of
files is given either on the command line or via
-T option. NUMBER defaults to 1.
--overwrite overwrite existing files when extracting
-O, --to-stdout extract files to standard output
--recursive-unlink empty hierarchies prior to extracting directory
--remove-files remove files after adding them to the archive
-S, --sparse handle sparse files efficiently
-U, --unlink-first remove each file prior to extracting over it
-W, --verify attempt to verify the archive after writing it
Handling of file attributes:
--atime-preserve don't change access times on dumped files
--group=NAME force NAME as group for added files
--mode=CHANGES force (symbolic) mode CHANGES for added files
-m, --touch don't extract file modified time
--no-same-owner extract files as yourself
--no-same-permissions do not extract permissions information
--numeric-owner always use numbers for user/group names
--owner=NAME force NAME as owner for added files
-p, --preserve-permissions, --same-permissions
extract permissions information
--preserve same as both -p and -s
--same-owner try extracting files with the same ownership
-s, --preserve-order, --same-order
sort names to extract to match archive
Device selection and switching:
-f, --file=ARCHIVE use archive file or device ARCHIVE
--force-local archive file is local even if has a colon
-F, --info-script=NAME, --new-volume-script=NAME
run script at end of each tape (implies -M)
-L, --tape-length=NUMBER change tape after writing NUMBER x 1024 bytes
-M, --multi-volume create/list/extract multi-volume archive
--rmt-command=COMMAND use given rmt COMMAND instead of rmt
--rsh-command=COMMAND use remote COMMAND instead of rsh
--volno-file=FILE use/update the volume number in FILE
Device blocking:
-b, --blocking-factor=BLOCKS BLOCKS x 512 bytes per record
-B, --read-full-records reblock as we read (for 4.2BSD pipes)
-i, --ignore-zeros ignore zeroed blocks in archive (means EOF)
--record-size=NUMBER SIZE bytes per record, multiple of 512
Archive format selection:
-H, --format=FORMAT create archive of the given format.
FORMAT is one of the following:
gnu GNU tar 1.13.x format
oldgnu GNU format as per tar <= 1.12
pax POSIX 1003.1-2001 (pax) format
posix Same as pax
ustar POSIX 1003.1-1988 (ustar) format
v7 old V7 tar format
-j, --bzip2 filter the archive through bzip2
--old-archive, --portability
same as --format=v7
--pax-option=keyword[[:]=value][,keyword[[:]=value], ...]
control pax keywords
--posix same as --format=posix
--use-compress-program=PROG
filter through PROG (must accept -d)
-V, --label=TEXT create archive with volume name NAME. At
list/extract time, use TEXT as a globbing pattern
-z, --gzip, --gunzip, --ungzip filter the archive through gzip
-Z, --compress, --uncompress filter the archive through compress
Local file selection:
--after-date=DATE same as -N
--anchored exclude patterns match file name start
--backup[=CONTROL] backup before removal, choose version CONTROL
-C, --directory=DIR change to directory DIR
--exclude=PATTERN exclude files, given as a PATTERN
--exclude-caches exclude directories containing a cache tag
-h, --dereference dump instead the files symlinks point to
--ignore-case exclusion ignores case
-K, --starting-file=MEMBER-NAME
begin at member MEMBER-NAME in the archive
--newer-mtime=DATE compare date and time when data changed only
--no-anchored exclude patterns match after any / (default)
--no-ignore-case exclusion is case sensitive (default)
--no-recursion avoid descending automatically in directories
--no-wildcards exclude patterns are plain strings
--no-wildcards-match-slash exclude pattern wildcards do not match '/'
--null -T reads null-terminated names, disable -C
-N, --newer=DATE-OR-FILE only store files newer than DATE-OR-FILE
--one-file-system stay in local file system when creating archive
-P, --absolute-names don't strip leading `/'s from file names
--recursion recurse into directories (default)
--strip-components=NUMBER strip NUMBER leading components from file
names
--suffix=STRING backup before removal, override usual suffix ('~'
unless overridden by environment variable
SIMPLE_BACKUP_SUFFIX
-T, --files-from=FILE-OF-NAMES get names to extract or create from file
NAME
--wildcards exclude patterns use wildcards (default)
--wildcards-match-slash exclude pattern wildcards match '/' (default)
-X, --exclude-from=FILE exclude patterns listed in FILE
Informative output:
--checkpoint display progress messages every 10th record
-v, --verbose verbosely list files processed
--check-links print a message if not all links are dumped
--index-file=FILE send verbose output to FILE
-R, --block-number show block number within archive with each
message
--show-defaults Show tar defaults
--show-omitted-dirs When listing or extracting, list each directory
that does not match search criteria
--totals print total bytes written while creating archive
--utc print file modification dates in UTC
-w, --interactive, --confirmation
ask for confirmation for every action
Compatibility options:
-o when creating, same as --old-archive. When
extracting, same as --no-same-owner
Other options:
-?, --help Give this help list
--license Print license and exit
--usage Give a short usage message
--version Print program version
Mandatory or optional arguments to long options are also mandatory or optional
for any corresponding short options.
The backup suffix is `~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX.
The version control may be set with --backup or VERSION_CONTROL, values are:
t, numbered make numbered backups
nil, existing numbered if numbered backups exist, simple otherwise
never, simple always make simple backups
*This* tar defaults to:
--format=gnu -f- -b20 --rmt-command=/sw/lib/rmt --rsh-command=/usr/bin/rsh
Report bugs to <bug>.
bob-lees-mac-pro:~ b0bMini$
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_________________
-πππ- (admin) - Robert P. Lee - Recordings - Breathe - D6th - Video |
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Jeff Hyman
From:
West Virginia, USA
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Posted 20 Oct 2008 11:07 pm
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Bob... that's what I was lookin' for!
TIA! |
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John Cipriano
From:
San Francisco
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Posted 25 Oct 2008 2:26 pm
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Here's the output of file on the firefox binary.
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mrjones:MacOS john$ file firefox-bin
firefox-bin: Mach-O universal binary with 2 architectures
firefox-bin (for architecture ppc): Mach-O executable ppc
firefox-bin (for architecture i386): Mach-O executable i386 |
Most Mac apps nowadays are compiled for both PPC and Intel and shipped that way. I have an Intel Mac.
OS X apps are Mach-O format, not ELF. There is no ldd or objdump. There is a program called otool for looking at headers, dependencies, hints table, etc. This link might be of interest to you:
http://0xfe.blogspot.com/2006/03/how-os-x-executes-applications.html
Disclaimer: I'm not a C coder. I don't know what a hints table is, just that they exist and people look at them sometimes  I do my stuff in scripting languages. |
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Jeff Hyman
From:
West Virginia, USA
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Posted 25 Oct 2008 3:46 pm
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| Thanks John. BTW: Don't knock scripting. My real comfort zone is bash scripting. |
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