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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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 ...
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votes
2answers
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Global bash_profile

I realize there are /etc/profile and /etc/bashrc files for setting global environment variables and maybe I'm just misunderstanding their purposes, but... Is there a global bash_profile file? I'm ...
9
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4answers
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How to use ifconfig to show active interface only

By default ifconfig will show me all available interfaces , but what if I just want to display active ones? Like, en0 only in below. en0: ...
9
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1answer
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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 ...
8
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4answers
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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 ...
8
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1answer
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+ or @ mark after running 'ls -al'

In Mac OS X, run 'ls -al' gives me something like this. drwxrwxrwx+ 4 smcho staff 136 May 5 09:18 Public drwxr-xr-x+ 6 smcho staff 204 Feb 1 2010 Sites drwxrwxrwx 9 smcho staff ...
8
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3answers
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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 ...
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4answers
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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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4answers
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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 ...
8
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1answer
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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: ...
8
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3answers
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Creating a Bash script that will execute a program and if it exits without crashing, will run it again

I'd like to know the easiest way of creating a bash script that will run an app in MacOSX (it's a UNIX based system so I assumed this was the right place). wait for the program to exit. If the exit ...
8
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1answer
72 views

OS X, bash: less works on open file descriptors, cat doesn't

In a bash script I'm working on (which has to run on Ubuntu and OS X), I need to redirect the output of hundreds of commands to a file. Rather than appending &>... to all of them, I simply do ...
8
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2answers
532 views

Prevent disk renumbering on reboot in OSX

I have 3 physical drives in my Mac Pro with OSX 10.6.4. Occasionally after rebooting the machine, the disk numbering changes such that the /dev/disk# does not reference the same drive as it did before ...
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5answers
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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 ...
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5answers
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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 | ...
7
votes
2answers
476 views

Does OS X have its own line format?

Obviously there are at least two newline types: DOS and Unix. But does OS X have its own plaintext 'format'? I opened a text file in nano and was surprised to see: [ Read 26793 lines (Converted from ...
7
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3answers
566 views

How to permanently change both STDOUT and STDERR color to grey?

This question is similar to Can I configure my shell to print STDERR and STDOUT in different colors? But I am looking for a solution that will allow me to change both STDOUT and STDERR to ONE color. ...
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3answers
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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, ...
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2answers
745 views

How to use the SVN CLI effectively

How can I make myself more productive with the SVN CLI? I need to complete repetitive tasks like these: find modified files in directory commit only SOME of them selecting them somehow other then ...
7
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4answers
3k views

Is there something like wine to run OSX apps on linux?

This question answers why Linux can't run OSX apps, but is there some application similar to Wine that allows one to do so?
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2answers
242 views

Hibernate and security considerations

How do Linux and OSX handle sensitive memory pages (e.g. cryptographic keys) when running OS is suspended to disk? If the memory image written is encrypted, how are its keys handled?
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2answers
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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 ...
7
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2answers
397 views

Bash inside Vim not working properly

In MacVim I'm using Conque to run bash commands inside Vim. I have a problem with the text navigation while using Conque. If I'm at the end of a line of text and press down Alt← I skip a word to the ...
7
votes
1answer
817 views

Screen cuts off beginning of long command when accessed through bash history

I'm using the default versions of bash and screen in OS X Lion. When I'm in a screen session and I scroll back through the bash history and I come to a command that is long enough to wrap. I might ...
7
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1answer
303 views

in zsh, how do I hide the backslashes in the completion menu

On Mac OS X 10.6, zsh. I have set in .zshrc: setopt automenu …to get a completion menu below the prompt. When I type: cd <TAB> I see a completion menu with all directories that have spaces ...
6
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4answers
239 views

How to grep-inverse-match and exclude “before” and “after” lines

Consider a text file with the following entries: aaa bbb ccc ddd eee fff ggg hhh iii Given a pattern (e.g. fff), I would like to grep the file above to get in the output: all_lines except ...
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10answers
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Install rEFInd on OS X 10.10 Yosemite

I want to dual boot my macbook with Arch Linux and thus tried to install rEFInd using the install script, however, after install rEFInd doesn't seem to start at all? Anyone experienced the same issue ...
6
votes
1answer
2k 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: ...
6
votes
2answers
498 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 ...
6
votes
2answers
2k 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
votes
1answer
5k views

How do I start a virtual machine in background upon OSX system start?

I have a virtualbox machine on a OSX 10.9.2 host. I do not want to open VirtualBox everytime and start the machine there. Also, I do not need the the screen output as I will just ssh from OSX terminal ...
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2answers
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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 ...
6
votes
1answer
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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 ...
6
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1answer
4k views

Does Windows recognize Linux's symbolic links?

I was just wondering how a Windows system handles symbolic links. My best guess is that it will not recognize them, but I'm not entirely sure. Also, what do Macs do when confronted by one?
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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
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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 ...
6
votes
1answer
4k views

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: ...
6
votes
1answer
673 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 ...
6
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2answers
757 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
1answer
91 views

Terminal does not accept pasted or typed lines of more than 1024 characters [duplicate]

When I enter text on stdin in an OS X Terminal, a single line is limited to 1024 characters. For example, cat > /dev/null beeps after I type (or paste) a line longer than this, and refuses to ...
6
votes
2answers
846 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
2k 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 ...
6
votes
1answer
560 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 ...
6
votes
2answers
402 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 ...
6
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1answer
373 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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2answers
2k 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 ...
5
votes
3answers
544 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
2answers
175 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 ...
5
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2answers
515 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 ...