Questions about the command line and other Unix-like aspects of Mac OS X, including the Mach/BSD-based kernel and FreeBSD-based userland. You may want to consider using Ask Different instead.

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36
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7answers
9k views

what does the @ mean in ls -l?

I am using Mac OSX. When I type ls -l I see something like drwxr-xr-x@ 12 xonic staff 408 22 Jun 19:00 . drwxr-xr-x 9 xonic staff 306 22 Jun 19:42 .. -rwxrwxrwx@ 1 xonic staff 6148 25 ...
31
votes
5answers
16k views

Is Mac OS X UNIX?

I have this argument recently saying Mac OS X was not UNIX, but Unix-like. I know there is a Single Unix Specification and those spec complaint could use the UNIX trade mark. Is Mac OS X an UNIX ...
5
votes
3answers
26k views

How to repair a corrupted HFS+ partition from a damaged hard-disk?

I have a friend's Mac OS X disk that comes with an HFS+ partition. I am supposed to recover the personal data from this disk, and I'm not yet sure if the filesystem is corrupted or the disk is dying). ...
27
votes
2answers
11k views

Where does Mac OS X come from?

Discussing with Mac owners, I got several versions of where Mac OS X comes from. It is known to have some root in BSD, but how much, and where? Some say that Mac OS X has a FreeBSD kernel, with all ...
15
votes
8answers
9k views

pgrep and pkill alternatives on mac os x?

Are there alternatives to pgrep and pkill commands on Mac OS X or should I just create aliases for them using other commands available for me?
64
votes
10answers
42k views

How do I know if dd is still working?

I've not used dd all that much, but so far it's not failed me yet. Right now, I've had a dd going for over 12 hours - I'm writing an image back to the disk it came from - and I'm getting a little ...
12
votes
4answers
5k views

If I connect a physical device, how can I ever know which device file belongs to it?

Say I plug in several USB drives which don't get automatically mounted. How can I find out which device file belongs to which physical device, so I can mount it for example? I'm running Mac OS X but ...
18
votes
4answers
1k views

Finding command execution time in hindsight

I've just executed a long-running process from the bash prompt. In hindsight, I wish I'd run time on it, or noted down the time at which I kicked it off. Is there any way of getting this information ...
8
votes
1answer
2k views

Bash history with timestamps

I would like to keep timestamps on the commands logged in my Bash $HISTFILE, is it possible? I did not manage to set it up using man bash as an information source. My other options are as follows: ...
2
votes
2answers
818 views

Key mappings in Linux

What do people mean when they point out that the "keys are not properly mapped" in a Linux installation when working on the command line? Isn't the default installation OK? What extra/specific ...
15
votes
2answers
4k views

Differences between sed on Mac OSX and other “standard” sed?

I am having some issues in using an answer provided on this site for this question about a sed command to replace a blank line with two other lines of content, and it was brought up if the sed command ...
15
votes
3answers
707 views

Why don't shell builtins have proper man pages?

All shell builtins share the same manual page: BUILTIN(1) BSD General Commands Manual BUILTIN(1) NAME builtin, ! etc. Then there is a little text describing ...
13
votes
6answers
1k views

Is there a root password on OS X and Ubuntu?

When you setup a new Ubuntu or OS X installation a user is generally created for you. On OS X it is whatever username you pick. On Ubuntu (the server version) usually the ubuntu user is created. The ...
6
votes
2answers
2k views

What should I be aware of when installing Linux on a Mac?

I have a Macbook Pro and I am loving it, though I still miss my Linux box, there are many things I need which are not completely compatible with Mac OS X. I heard many stories about installing Linux ...
2
votes
2answers
3k views

Best options for mounting Mac OS X hard drive on my Linux box?

I have a new 3 terabyte external USB hard drive (Seagate ST3000DM001 in an enclosure). I hope to use it on both my iMac (OS X 10.6.8) and my Linux machines (Kubuntu). Right now this drive will ...
7
votes
5answers
3k views

How to make bash put prompt on a new line after cat command?

What I get: host:~ user$ cat example.txt some texthost:~ stas$ What I want to get: host:~ user$ cat example.txt some text host:~ stas$ Is there a way I can make cat behave like this? I'm using ...
11
votes
3answers
1k views

Why are interactive shells on OSX login shells by default?

In Linux and, to my knowledge, all Unix systems, terminal emulators run interactive, non-login shells by default. This means that, for bash, the started shell will: When an interactive shell that ...
8
votes
4answers
2k views

Directory size calculation difference

I need to get the size of directory in terminal for signing purposes. I'm using following command: du -s /path/to/dir I'm multiplying the result by traditional UNIX block size (512 bytes) and get ...
4
votes
1answer
980 views

Mac OS X Darwin: how to reset admin password?

Today I bought an ibook G4 from a garage sale. The people who sold it to me didn't know the password for the 2 accounts on it. Apparently it was the guys late father's laptop. Any suggestions on how ...
2
votes
1answer
269 views

Using setuid Properly

I've been scared too much by the warning about setuid. However I cannot find a way around using it. I want to be able to run: arp -s 198.51.100.1 00:53:00:12:34:56 as the user steven but arp -s ...
1
vote
1answer
97 views

osx server, windows client, running emacs opens it on server not client

I've installed emacsformacosx on my OSX box. I'd like to shove my macmini in a data center and run it headless. I've gotten x-windows working. If I run xeyes, it displays on my Windows 7 client. ...
0
votes
1answer
176 views

Using the cURL command, how does one fetch stock data which comes back *without* commas and spaces?

What can I add to the below script so that it fetches the stock data and brings it back WITHOUT any commas and spaces? For example GOOG Outstanding shares is 675,000,000. I desire the output of ...
0
votes
3answers
1k views

How can I (and should I) use my Linux file server as a Time Machine backup server for my Macs?

I have two Macs that I'd like to start backing up using Time Machine, but all of my storage is attached to my Linux file server. How can I use my Linux file server (which happens to be running Ubuntu ...
38
votes
6answers
8k views

Software developer switching from Linux to OS X, what are the gotchas?

I have used Ubuntu/Fedora/Red Hat/Suse but haven't used OS X at all. If I have to start using OS X regularly, what are the things I should look out for? Tools I use are GNU tool chain, C++/Boost, ...
14
votes
6answers
19k views

How can I page up or down in tmux with Terminal.app?

I have tmux installed. But I can not scroll up or down. I.e. as soon as I tmux I get only a portion of the screen and can not scroll up. crtl-b + Page Up does not work since I am in Mac and I can not ...
17
votes
5answers
22k views

How to persist ulimit settings in OSX Mavericks?

Before Mavericks, one could use /etc/launchd.conf to persist ulimit settings, for example: limit maxfiles 16384 unlimited limit maxproc 16384 unlimited It no longer works in Mavericks. What is the ...
21
votes
3answers
10k views

File system compatible with all OSes?

I use Linux and Mac OS X on a regular basis, and sometimes I have to use Windows. I need to use a flash drive on all three, and I need a filesystem that will work well on all of them. None of the ...
22
votes
4answers
8k views

What makes OSX programs not runnable on Linux?

I know there are many differences between OSX and Linux, but what makes them so totally different, that makes them fundamentally incompatible?
11
votes
5answers
2k views

Using text from previous commands' output

EDIT April, 2015: If you have this same question I recommend also checking http://xiki.org/ I know this is not how terminals work, but I find myself often wishing there was an easy way of using ...
20
votes
6answers
15k views

How do you create a user with no password?

In os X it's possible to have users without passwords. If you inspect them with dscl their password show up as *. This is used for system users such as users for databases like mysql, pgsql etc. ...
9
votes
5answers
3k views

pv for directory copy

I need to copy a very large directory (talking in terabytes here) and want to monitor the progress. I found that pv is a nice utility, but how can I use it for copying directories recursively? (pv ...
7
votes
4answers
5k views

sed on OSX insert at a certain line

So I've been using 'sed' on linux for a while, but have had a bit of difficulty trying to use it on OSX since 'POSIX sed' and 'GNU sed' have so many little differences. Currently I'm struggling with ...
7
votes
5answers
4k views

How to copy all html files from a directory tree to a single directory?

I want to copy all the .html files in myDir and its subdirectories to ~/otherDir. Here's what I tried (it doesn't work): $ find myDir -name *.html -print | xargs -0 cp ~/otherDir usage: cp [-R [-H | ...
14
votes
6answers
2k views

OS X: how to keep the computer from sleeping during a ssh session

When I ssh into a OS X computer on my network the session lasts until the OS X goes into sleep mode. Is there a way to prevent this from happening during my SSH session, apart from physically bumping ...
10
votes
2answers
1k views

Is it OK to use “.” to run files instead of source - in .bashrc in Ubuntu and OS X?

OK, so source runs the script in the current shell and . separately, as detailed in running script with ". " and with "source " for example, but, specifically, in my .bashrc file, ...
11
votes
6answers
1k views

Disable Keyboard & Mouse Temporarily

I would like to know how one can disable the keyboard & mouse temporarily in OS X.
9
votes
4answers
1k views

Use #!/bin/sh or #!/bin/bash for Ubuntu-OSX compatibility and ease of use & POSIX

I know that I can use either as the first line of scripts to invoke the desired shell. Would #!/bin/sh be recommended if compatibility with all unix systems is an absolute requirement? In my case ...
8
votes
3answers
3k views

How can I print well formatted code

Similar to using markdown on Stack Overflow to create monospace output, how can I do that for my programs. I tried lp filename.txt and was pleasantly please to find that it was able to use the local ...
4
votes
2answers
3k views

To grep 20 characters after and before match

I have the problem that I get too much information after the match for grep -RnisI --color=auto "pseudomonas" * I want to get only like 20 characters or 10 words after and before the match. What ...
4
votes
5answers
896 views

If Mac OS X is UNIX, why is it that it is not open sourced and the license is proprietary?

If Mac OS X is a Unix, as answered in this question, why is it that it is not open sourced and the license is proprietary, as stated in this Wikipedia article? According the the genealogy from this ...
1
vote
1answer
1k views

Safe to change owner of OS X system folders?

I'm trying to get Homebrew to work. That program's diagnosis tool gives me these suggestions: You should probably chown /usr/local/etc ... You should probably chown them: ...
9
votes
1answer
6k views

Why the value of VSIZE in top is different from the value of VSZ (Virtual set size) in ps?

I know VSZ in ps is for the total address space allocated for the app and is sometimes aliased as vsize (mentioned in man page of ps on linux), but what's the definition of VSIZE in top? This top ...
6
votes
1answer
1k views

How to persist ulimit settings in OSX Yosemite?

Previous question about doing this on Mavericks is here and the answers there don't seem to work on Yosemite. I want to enable core dump generation by default upon reboot. Executing ulimit -c ...
4
votes
2answers
128 views

sed: inserting text before end of <HEAD> section

I need to insert some text into an HTML file before the end of the HEAD section. I'm trying: sed -i "s#</head>#<style> @page { prince-shrink-to-fit: auto } ...
4
votes
1answer
694 views

Routing Tables: What is the effect of the RTF_IFSCOPE flag?

(Related to this question I posted a while ago on apple.stackexchange.) What is the difference between the following two routing table entries: default E.F.G.H UGSc 0 ...
3
votes
3answers
61 views

Is swapping enabled by default on common operating systems?

As a result of this question, I was a bit confused. After some research I found that swapping is enabled by default on Mac OS X. Swapping was furthermore introduced in Windows 3.0, so I believe it is ...
3
votes
2answers
489 views

Ruby update not working using two methods

I tried to install ruby version 1.9.3 with this on my mac 10.6.8: $ \curl -L https://get.rvm.io | bash -s stable --ruby Oskar-Niburskis-MacBook-Pro:~ oskarniburski$ rvm install ruby-1.9.3-p362 ...
3
votes
1answer
2k views

How can I create a shortcut to resize panes in a tmux window?

I am having lots of issues with tmux in mac. Another problem I have is that I can not bind a key in my tmux.conf to be able to resize my panes. What I need is the CTRL-b: resize-pane -U 10 I currently ...
3
votes
3answers
1k views

Issues with .bash_profile and terminal commands

I added some data to my .bash_profile to run two aliases ruby version 19 and the proper gems. As soon as I added the data I could not longer run any commands such as the MacPorts command port nor the ...
3
votes
2answers
244 views

How to bind “ß” to Meta-s?

I am using Carbon-Emacs on MacOS X 10.6 with the US-International keyboard layout. Usually, I can use Alt+s to print the letter "ß". However, Emacs interprets this as Meta+s and complains that there ...