Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs.

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Linux-like top/netstat/etc. on Mac OS X?

Unix utilities on Mac OS X are quite painful to use. port install coreutils +with_default_names and a few other such replacements fix most of them, but it leaves some in broken Mac OS X defaults - ...
15
votes
1answer
736 views

Make Firefox use the favicon as window icon under Linux

Is there a Firefox feature, setting, or add-on that arranges it so that the favicon of the currently open web page becomes the icon of the browser window in Linux/X11? In particular, it ought to show ...
14
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7answers
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Is there a way to go to any directory from any other directory directly?

Is there a way to go to any directory from any other directory directly? For example, lets say that I'm at root and I wanted to go directly to currentProject without doing: cd ...
14
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3answers
16k views

what is the max length of password on unix/linux system?

what is the max permissible length of password on unix/linux system?
14
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7answers
23k views

How to make a statement that checks if something is divisible by something else without a remainder (BASH)

#!/bin/bash Echo “Enter a number” Read $number If [$number ] ; then Echo “Your number is divisible by 5” Else Echo “Your number is not divisible by 5” fi the if [$number] statement is what ...
14
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3answers
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UNIX - mount: only root can do that

I need to allow a non-root user to mount/unmount a device. I am a total noob when it comes to UNIX, so please dumb it down for me. I've been looking all over teh interwebz to find an answer and it ...
14
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2answers
10k views

How to make files created in a directory owned by directory group?

Is there a way, on Linux, to cause all new files created in a directory to be owned by the directory's group instead of the creating user's group?
14
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2answers
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what does the @ symbol mean in ls -l directory listing? [duplicate]

Possible Duplicate: ls -la symbolics… what does that last symbol mean? When I run ls -l on my mac I see two .yml files: -rw-r--r-- 1 aa staff 6 Apr 15 05:50 s1.yml -rw-r--r--@ ...
14
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2answers
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Unix: Is there a way to “copy” file or directory permissions?

I have two files in a directory. One has correct permissions and the other has not. Is there a way I can "copy" the set of permissions from one file to another?
14
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2answers
13k views

Why do we use cp to copy files and not dd? (in unix-derivatives)

For normal file copying in *nix, I've only ever seen people use cp (eg. cp /mnt/mydevice/myfile ~/myfile), but I eventually ran into dd, which appears to do the exact same thing (dd ...
13
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4answers
19k views

Do symbolic link files survive SVN?

Let's say I create a symbolic link file inside an SVN managed path, commit the path to SVN and later checkout the path. 1) Will the symbolic link file survive? 2) If the symbolic link file is made ...
13
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3answers
5k views

How to read Unix usage

I did some searching, but I cannot find documentation on how Unix usage works. I know something (mostly through trial and error) but, for example, how do I know that /usr/bin/ls ...
13
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8answers
2k views

Is there a command for going back a number of steps in a directory, without using cd?

I'm constantly going 'cd ../../../../'. Is there a command/alias that could let me go 'cmd 4' and I'd be taken back 4 directories?
13
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3answers
19k views

What does kill -3 mean?

I know kill -9 mean, but anyone can explain what does kill -3 mean? Any special signal it sends out?
13
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2answers
18k views

How to keep program running after SSH disconnection? [duplicate]

Possible Duplicates: Keep a program running after closing a console, after the program has started How can I use ssh to run a command on a remote Unix machine and exit before the command ...
13
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5answers
386 views
13
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7answers
16k views

Is it better to always copy and delete, rather than move?

Generally speaking, I find myself panicking when I realise that if I cancel a file move, it could cause the target or source to be incomplete. This question applies to Windows and Unix-based ...
13
votes
7answers
8k views

Sorting human readable file sizes

How can I sort a list using a human-readable file-size sort, numerical sort that takes size identifier (G,M,K) into account? Can I sort "du -sh" output for example? Problem: Consider the problem of ...
13
votes
7answers
11k views

Advantages of cat'ing file and piping to grep

Are there any additional advantages of cat'ing a file and piping it to grep, besides convenience? The convenience being that, when I retrieve commands such as those below from my history, the cursor ...
13
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3answers
30k views

How to display Unix time in the timestamp format?

I'm looking for a way to display my time in Debian Linux as a timestamp, e.g. 1279628325 I can't find any options to do that with the date command. Any ideas?
13
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4answers
8k views

How can I recursively grep particular files in a directory?

I'm new to linux and grep, and trying to find my way around. By using find -name *.java I am able to find the names of all of the java files in a particular directory. Suppose I want to count the ...
13
votes
1answer
26k views

In UNIX, what are the Ss, Sl, and Ssl proccess types I see with ps aux?

When doing a ps aux command, I see some process listed as Ss, Ssl and Sl. What do these mean? root 24653 0.0 0.0 2256 8 ? Ss Apr12 0:00 /bin/bash -c /usr/bin/python ...
13
votes
1answer
22k views

Console commands to change virtual ttys in Linux and OpenBSD

In Linux one presses Alt-F1, Alt-F2 etc to change virtual ttys. In OpenBSD one shall use Ctrl-Alt-F1 etc instead. Are there are console commands for these two operating systems that can be issued to ...
13
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9answers
8k views

“Detach” and “Reattach” xterms across X sessions?

Is there a way to save/detach an xterm (or another window), and reopen/load/reattach it on a different X session on the same machine ? What I'm trying to achieve is "move" running xterms between two ...
13
votes
3answers
7k views

Using `find` for multiple file extensions

I am using the following command for counting the lines of text in JAVA files: find . -name '*.java' | xargs wc -l How can I modify the find command parameters to match more than one file ...
13
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1answer
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What do the “ALL”s in the line “ %admin ALL=(ALL) ALL ” in Ubuntu's /etc/sudoers file stand for?

What does each ALL mean? I understand that the whole line indicates that the admin group members get admininstartive privileges, but would like to know more info about the position of the ALLS and if ...
13
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2answers
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Linux - alternative places where to store pid file instead of /var/run

As written in the title, where should I let the init script write the pid file? are there any standard paths I should choose instead of the /var/run ? Could /tmp be a good place where to store it or ...
13
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4answers
11k views

Vim highlighting for specific file types (where to put syntax files, vim events, line to put into vimrc)

I have defined a file time jak.vim to offer custom highlighting when I take notes, however it is being applied to some files that do not have the .jak extension. Specifically a file named ...
12
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5answers
3k views

How do we pronounce “/etc” folder? [closed]

Can't find similar question in SU. Anyone knows? Is it only 3 letter e,t and c? I can't find similar things in google. It would be good if someone provide this answer
12
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5answers
3k views

Map “untar” to tar xvfz?

How can I map 'untar' as a command to 'tar -xvfz' ? Sorry, but I almost always forget the arguments necessary to 'tar' for this operation.
12
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3answers
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Delete files with regular expression

I Tried to delete files that starts with A and ends with 2 numbers but It doesn't do a thing. What I tried: rm ^A*[0..9]2$ Where am I wrong?
12
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5answers
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How to jump back to the first character in *nix command line?

When writing a long command in the *nix command line and having to go back to the first character, in order to add something at the beginning (for instance a nohup, when you realize the process will ...
12
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7answers
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Best practices to alias the rm command and make it safer

Some time ago I erroneously deleted my home folder because I ran a rm -rf * on the wrong terminal, whose working directory was the home folder! I wish I had an alias for the rm command, but it was ...
12
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7answers
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How can I sort all files by size in a directory?

How can I display the files in a unix directory sorted by their human readable size, going from largest to smallest? I tried du -h | sort -V -k 1 but it does not seem to work.
12
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8answers
36k views

Tell `ls` to print only the base filename

This is the default behaviour of ls ls /net/nas/data/languages/pypm/sites/rex/free/2.6/*/pool/v/vi/virtual*1.4.4*pypm ...
12
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4answers
2k views

Who deals with the star * in echo *

Who deals (interprets) the * in echo * Does the echo see the star or the shell take care about it and return a list of filename .. What about cp temp temp*
12
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2answers
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Compress files from OS X terminal?

In the Finder, there is this wonderful ability to right click on a file or directory, select compress from the drop-down, and end up with a zipped file. Is it possible to do the same thing from the ...
12
votes
4answers
8k views

How to replace part of a text file between markers with another text file?

Say I have a text file like this: # custom content section a b ### BEGIN GENERATED CONTENT c d ### END GENERATED CONTENT I'd like to replace the portion between the GENERATED CONTENT tags with the ...
12
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2answers
1k views

Why does redirecting the output of a file to itself produce a blank file?

Why does redirecting the output of a file to itself produce a blank file? Stated in Bash, why do less foo.txt > foo.txt and fold foo.txt > foo.txt produce an empty foo.txt? Since an ...
12
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4answers
10k views

Terminal Vs. Shell [duplicate]

Possible Duplicate: What are the differences between shell , console & terminal? This probably sounds like a stupid question but I'm having a lot of trouble clearly differentiating ...
12
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1answer
11k views

What's a good way to install “build essentials” (all common useful commands) on a blank EC2 Linux server?

I want to get some "build essentials" (like gcc, make, etc.) on an empty micro Linux box. Seems inefficient to spend my time trying to try installing one thing, then realize I need gcc, then realize ...
12
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2answers
3k views

Unix: Slash after directory names or not

What is the difference between the following commands? mv foo bar mv foo/ bar/ mv foo/ bar mv foo bar/ Or is there no difference? Or does it depend on the command being used? Think for example I ...
12
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2answers
22k views

Subsystem for UNIX-based Applications in Windows 7

Noticed a thing called Subsystem for UNIX-based Applications in the Turn Windows features on and off dialog under Windows 7. Never seen it before, and it seems interesting. What exactly is it really? ...
12
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5answers
16k views

How to move only files in Unix

How can I move only the plain files (not the directories) from one folder in Linux to another folder using the mv command? I have tried mv * ~/, but it copied everything including the directories.
12
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3answers
11k views

Opposite of tail: all lines except the last n lines

How can I discard the last n lines of a file with a unix command line filter? That would be sort of the opposite of tail: tail discards the first n lines but pipes the rest through, but I want the ...
12
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3answers
3k views

Making Linux shell prompt show last return value

I'm currently on a Linux machine and the shell prompt is showing me the last return value and number of executed commands (picture included, with these numbers shown in purple). My own computer ...
12
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3answers
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Why are there short and long alternatives for command line options?

Most unixoid commands feature short and long alternatives for command line options, like ls -a and ls --all, or ls -A and ls --almost-all. Why do those two ways exist? One is shorter to type, the ...
12
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7answers
2k views

Is there any functional-like unix shell?

I'm (really) newbie to functional programming (in fact only had contact with it using python) but seems to be a good approach for some list-intensive tasks in a shell environment. I'd love to do ...
12
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3answers
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groupadd/useradd not found on Mac OSX

Does anyone know how to add unix groupadd command on Mac OSX 10.5? I'm trying to do man on groupadd and useradd commands but it doesn't seem to exist.
12
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5answers
7k views

What is a “pipe” and how can it be “broken”?

I've gotten the "broken pipe" error from Xcode one time too many. I'm now curious to know exactly what a pipe is. What is the concept of a "pipe" and how can it be "broken"?