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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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 ...
6
votes
3answers
1k views

How can I print good looking 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 ...
6
votes
2answers
1k views

Which is the best practice when replacing a system binary?

I'm working on Mac OS X which is shipped with several binaries mostly located in /usr/bin/ and /usr/sbin/. Since it doesn't have a native package manager like some Linux distros, I got used to ...
6
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3answers
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Mac OS X: dircolors not found?

I just switched to a Macbook Air. I installed zsh using homebrew, but when I use some of the code that I (originally had) in my .zshrc, I get an error saying that .dircolors was not found. Below is ...
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2answers
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SSH LocalCommand on exit

In ~/.ssh/config you can use the LocalCommand directive to execute a local command whenever you connect to a remote machine via SSH. But how do I execute a command when I exit an SSH connection? It ...
6
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2answers
106 views

Why do some applications stop working when permissions are changed in /usr/bin?

On OS X, a friend of mine changed the permissions on /usr/bin recursively using Finder, in order to grand write access to everyone. Here is how it's done: Go to /usr/bin in Finder, then mess with ...
6
votes
2answers
76 views

How do I only undo pasted text in vim?

TL;DR; version - How do I undo text that was pasted in from my OS copy buffer without undoing other text that was typed in since I went into insert mode? Longer description: Put something in your ...
6
votes
1answer
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What does the “@” (at) symbol mean on OSX ls? [duplicate]

When I check permission of less files from the command line on my Snow Leopard OSX system using Bash I see -rw-r--r--@ for certain files and for others I just see -rw-r--r-- What does the @ mean here? ...
6
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2answers
461 views

FHS differences between OS X, Linux and FreeBSD

I've read that there is a different behavior between FreeBSD and Linux with the /usr/local, in FBSD ports are installed there, in Linux not, can someone explain more on this? I'd like to know where ...
6
votes
1answer
344 views

Why wouldn't a symlink to a symlink work?

I've run into a weird issue when installing SWI-Prolog using homebrew on my OSX 10.9 box. I'm trying to debug it to figure out whose bug it is (SWI-Prolog's, homebrew's, or OSX's), so I can report it ...
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2answers
1k views

How similar is Apple's terminal.app to a bash terminal on Linux?

I know that Apple's Terminal.app provides a bash shell. Are there any differences between this and a bash on Linux?
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3answers
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How to cd to a Windows file share?

At work, I spend a lot of time manipulating files on a networked computer that's running SME Server (but that's set up for Windows filesharing, if that somehow makes a difference). I have been ...
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3answers
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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 ...
5
votes
3answers
523 views

Any tips for surviving Terminal.app?

I've recently switched to using a Mac full-time, and am having trouble getting used to Terminal.app after years of loving gnome-terminal. I miss having URLs show up underlined, using alt+arrow to ...
5
votes
1answer
429 views

What is equivalent to Mac's purge in Linux?

In Mac I use purge to free up some memory. What is equivalent to it in Linux(Ubuntu Server)? apt-get install purge gave me nothing. If you are no familiar with Mac's purge here is it's man page: ...
5
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2answers
243 views

Prevent a file from being deleted even after rm -f

I usually stay on StackOverflow but I think on this topic you guys are much more experts here. So today's exercise is weird, I have to write a script.sh and in it do whatever I can to prevent ...
5
votes
1answer
786 views

Where to install applications

I'm a long-time Windows user in the middle of a multi-year personal migration to Linux-based development. On Windows when I installed an application it got put in the Program Files folder and I'd ...
5
votes
3answers
168 views

Extracting data from complex file structure

I have a txt file that is a dump from a database, that contains one entry per line. The structure is like this: 1500 29/03/2010 18 02 09 47 17 45 28.248 0 0.01 130 12.721 7908 298,809 YES ...
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votes
2answers
331 views

Zsh: Automatically modify executed command

I've recently installed grc (generic colorizer) to my system via MacPorts, giving me the ability to get colorized output for plenty of commands which by default don't support it (see screenshot ...
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votes
3answers
2k views

Grep_color on mac

I am trying to get my regex highlighted on mac using terminal. I have put this is my .profile: export GREP_COLOR='1;30;40' Nothing changes, so I added the same to my bash.profile still nothing, ...
5
votes
2answers
875 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 ...
5
votes
2answers
5k views

rsync “skipping non-regular file” when cloning my Aperture library

I am trying to use rsync to maintain a backup copy of my Aperture library. When I run the sync command to see what would happen this is the outcome: rsync --dry-run -r "/Volumes/Data/Aperture ...
5
votes
2answers
291 views

Is it possible to record audio directly to a computer's optical drive?

There's a question over at audio.SE at the moment and I thought it may attract some answers here. I asked the user and he's happy to have it posted here to see if anyone has some ideas. Here it is ...
5
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3answers
142 views

Mac OS X find/grep generating “unknown --devices option”

I am entering a command I have done often with Linux, Unix perfectly fine but with Apple Mac OS X 10.8 (and probably before) I get a grep: unknown --devices option when I attempt to run the following ...
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votes
1answer
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Calculate the date from 1125 days ago on non-GNU systems?

On the Unix Bash commandline, I want to calculate the date from 1125 days ago using the base operating system (e.g. No Perl or Python). On systems running GNU Date, I can do something like this: ...
5
votes
1answer
564 views

How do I share applications windows between OS X and Linux?

I originally asked this question over on Super User, but I didn't get any answers. I'm trying to set up Xdmx on my Macbook Pro and my Ubuntu 10.04 workstation so that I can share my MBP's keyboard ...
5
votes
1answer
337 views

DTrace to trap any chmod applied to certain files

Underneath the Mac OS X directory /audit I have certain files which users can access and chmod to their liking. I need to audit any chmod done on any files by recording the time, user and file being ...
5
votes
1answer
499 views

How can I search/browse in some process's memory?

I'm using MacOS X 10.7 and I'm not very familiar with unix. Is there a command for a search in some process's memory for a string?
5
votes
1answer
454 views

Explain to a Linux user how do BSD/OSX drivers work

Linux drivers come in a form of kernel modules (*.ko files), which can be given parameters when loaded into the kernel and usually live in /lib/modules/<kernel version>. What's the similar ...
5
votes
1answer
182 views

Execute multiple bash commands on the output of find

I want to execute some commands using the find -exec option, but I'm not sure what' wrong with this code. Currently, it's only processing the first find result, then getting stuck. I'm using bash in ...
5
votes
1answer
346 views

How to create yaboot partition using a ppc Mac

My computer g4 1.5 ghz PowerBook ppc I need to use this computer to make a yaboot partition on a USB stick. Here is documentation for making a yaboot partition with a Linux machine: ...
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5answers
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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 ...
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5answers
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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 ...
4
votes
2answers
127 views

run perl script with unknown perl location

I'm developing a perl script which expected to be downloaded by Mac users with a very small knowledge of shell, linux etc, let's say office managers and accountants. After the downloading the script ...
4
votes
2answers
904 views

Tell if a folder/file is hidden in Mac OS X

I know you can set or unset the hidden flag of a folder/file by doing chflags hidden foo.txt and chflags nohidden foo.txt. But is there anyway of telling whether the folder/file is currently hidden ...
4
votes
1answer
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find & sed (search and replace)

I'm using the following command on my mac: $find . -name “*.java” -exec sed -i ’s/foo/bar/g’ {} \; and it seems to have no effect. I have two files in the directory that end in .java, which both ...
4
votes
3answers
193 views

OSX: dd quits after a few minutes

I'm trying to diagnose a possible disk problem on my OSX machine: I heard some funny noises, so I decided to do a read test of the entire disk using dd. A few months ago this worked: dd would run ...
4
votes
2answers
893 views

remove duplicate files

On my Mac OS X 10.6.7, iTunes duplicated every single file in my music library. Now I have 3,840 files instead of 1,920. The problem is that iTunes didn't simply duplicate the whole folder, but each ...
4
votes
1answer
8k views

chmod: What does the `+a` parameter mean?

I was following a tutorial and it told me to run sudo chmod +a "SOME_PARAMS" some/dir I was surprised to see that fail telling me chmod: invalid mode: `+a' So I wonder: What does the +a mode ...
4
votes
3answers
264 views

Send a specific signal to an external USB keyboard? Or, how do I fix fdopen()?

Some background: I'm trying to make the caps lock light on an external keyboard light up on-command when I run a command from the command line. Ideally it would be scriptable, so that I can use it for ...
4
votes
2answers
298 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
2answers
214 views

Why does du report a size of 0 for some non-empty files on a HFS+ partition?

What is the explanation for the difference: $ ls -l /Applications/Safari.app/Contents/Info.plist -rw-r--r-- 1 root wheel 15730 11 jui 15:02 /Applications/Safari.app/Contents/Info.plist $ du -sh ...
4
votes
1answer
189 views

terminal - having “$” instead of MyComputer:~ me$

Right now in my MacOS X terminal I have MyComputer:~ me$ before all the commands. In some videos I saw they have just $ - that's much less clutter, how is it done?
4
votes
3answers
509 views

How to find a file with specific permission of a specific user?

How do I get a list of all the files which permission is "read and write" for a specific user. For example, when I go on the desktop of my mac, then right click on file "A", then "get info", then on ...
4
votes
2answers
2k views

Spaces as line breaks from inline for loop command

Someone care to enlighten me as to why the spaces in the first command seem to be interpreted as line breaks? Also occurs substituting print for echo. $for l in $( find *.txt -exec head -1 {} \; ); ...
4
votes
1answer
12k views

How to know when and which user logged into the system under Mac OS X? Last is not enough!

In Mac OS X, if I don't touch it for a while, it will lock the screen and one must use password to unlock it, but this kind of log in is not recorded by last command. I want to know if anybody tried ...
4
votes
1answer
2k views

Sharing Mac Snow Leopard directory via NFS

I am running a Mac Pro using Snow Leopard (not server). I would like to share a directory with a linux machine. I have edited /etc/exports on the Mac to: /Volumes/mstore/home/sdavis -maproot=root ...
4
votes
3answers
246 views

Best way to work through / display a tree of images sorted by size

I've got a deep directory tree containing .PNG files. I'd like to find all the .PNG files in the directory, sort them in order of size from smallest to largest, and then display every 50th image. ...
4
votes
1answer
3k views

Stuck process: is it a bad sign?

Sometimes a few process are in a stuck state. For example: PID COMMAND %CPU TIME #TH #WQ #POR #MREGS RPRVT RSHRD RSIZE VPRVT VSIZE PGRP PPID STATE 99357 plugin-container ...
4
votes
1answer
203 views

Where does GCC look for its internal executables?

I have installed GCC to a custom prefix. When it is invoked, it complains that it cannot find some of its internal binaries. My computer's "official" GCC keeps them here: ...