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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Unable to SSH, cannot create /dev/null/.ssh

I am trying to deploy hadoop with a master and slave node. But the master fails to start tasttracker and datanode processes in slaves, as it is not able to ssh into slaves. The error message is 'Could ...
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2answers
211 views

using url with Putty to access Unix server

I need to access UNIX server from my windows machine and will be using PUTTY. Can I access the UNIX server with the url rather than direct IP address? I am getting error that host cannot be found ...
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200 views

which unix or linux command is used to change root password of remote machine(Just an IP address) without using SSH Login

which unix or linux command is used to change root password of remote machine(Just an IP address)? Suppose I just have an IP address of the target machine which is on my network, But I do not know ...
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5answers
379 views

Little clarity needed about: PC and Mac and Unix

I've always thought that a PC and A Mac were two different computing platforms, not just with in their operating systems (Windows & Mac OS) but different from hardware to thier respective internal ...
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2answers
96 views

Formatting a file for sendmail

How can I format a file so I can just do cat file | sendmail? By putting Subject: This is the subject, I don't need to specify the subject in sendmail, but adding the To: myemail@hostname.com field ...
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54 views

Is there any limitation on file names under Unix?

We are using crontab to schedule jobs and it was not picking the files for processing that contain [ or ] or ¿. Is there any limitation on file names or do these characters mean something in UNIX? ...
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1answer
512 views

Remove question mark “?” from file names OSX

My music library contains many .flac files that need the "?" removed from the filename as my current music player (Sonos) cannot for some reason see those files. Is there a command or script that ...
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1answer
292 views

Can I tell if I'm in an scp session in my .bashrc?

Inside my .bashrc, I'm doing a bunch of magic that causes problems when I'm trying to do an scp. The solution I've been going with is to manually ssh to the target machine, disable my .bashrc, do the ...
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2answers
38 views

Using only 1 command line, how do I write a command to that will do a long list of all files in the storage/file directory

Using only 1 command line, how do I write a command to that will do a long list of all files in the storage/file directory and pipe the output to a grep command that finds all items containing the ...
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3answers
76 views

What is the effect of using a # in front of a UNIX command?

My guess from the working of it is that it suppresses the output of the command
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2answers
178 views

How to close firefox service from putty?

How can i close firefox service from putty?? I have tried using service command.. But i don't know the exact syntax.. I am getting following warning box Firefox is already running, but is not ...
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1answer
452 views

How to call and launch EXE from linux \unix side?

I have a build process that runs on Linux and UNIX hosts. It's script -based, and at the end of the process I'd like to run an EXE file (that can run on Windows only... yes I know it's quite weird but ...
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1answer
638 views

Map `php` at the command line to point to `/usr/bin/php`?

For some reason using php at the command line references /usr/local/bin/php instead of /usr/bin/php. How can I make $ php script.php the equivalent of running $ /usr/bin/php script.php? Current ...
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1answer
95 views

Attach screen on a running terminal

I have a long running process in a (virtual) terminal that unfortunately was not started in a (gnu) screen session. Is there a way to migrate it in a screen session? (obviously, without stopping it) ...
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1answer
416 views

How to make terminal title to stick on Macs

I'm not sure if this is a problem with my mac, of which I'm a noob with, or if it's a setting of the server I'm sshing into. What I'm doing is this: Open a new window in terminal SSH into a CentOS ...
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2answers
440 views

Writing Unix script (bash) that creates a directory in the location specified at the command line

I currently have a Unix script (written in bash) that executes several commands to modify a group of files, which I specify with an flist containing their paths. The general idea of the script is to ...
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1answer
1k views

UNIX command to sort the file by the following words, from major sort key to minor sort key: word 3, word 1, word 4

Need help with the UNIX command below to sort the file by the following words, from major sort key to minor sort key: word 3, word 1, word 4. (words are separated by white spaces) sort -t -k3 -k1 ...
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2answers
146 views

Silent cd using cdpath with zsh?

When using cd to navigate to a path found by cdpath that is not located relative to ., the resulting path gets echoed. For example, assuming a directory structure like ~/parent/child and a cdpath like ...
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1answer
545 views

How to use chmod to change a file's permission?

I used ls -l to find file permissions in a shell and found this: File 1: -rw-r--r-- 1 root root 451 Mar 9 15:25 file.class.php File 2: -rw-rw-r-- 1 andy dev 872 Mar 9 15:43 file.class.php I want ...
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1answer
1k views

Grep issue (match two strings on same line)

Here I have some grep command which is not working correctly: cat file1.txt: apples Date: Sun, 24 Feb 2013 8:14:06 -0800 peaches melons cherry sky cloud green purple yellow cat file2.txt: apples ...
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1answer
217 views

the effect of large number of files on disk space in unix filesystems

If I have a text file in Unix that contains N-many independent entries (e.g. records about employees, where each employee has a separate record), is it expected that this file will take up less space ...
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2answers
403 views

File doesn't exist in Linux although it's located in Terminal

I'm a bit new to unix/linux environment, but I have a small problem. I'm using "locate" to find the path of a file I need, it gives me the path for it, but the file doesn't exist in that path, like ...
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1answer
117 views

differnce between blocksize and bytesize in linux/unix filesystems

Can anyone discuss the exact difference between block size and byte size, when it comes to disk sizes for Linux/Unix filesystems.
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2answers
157 views

Shell script: Copy folder with a new name

I'm trying to write this shell script to create in the parent directory a copy of the folders found in the current directory. So far, I wrote this: for folder in *; do mkdir ../$folder; done ...
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1answer
2k views

Find out which port the daemon is using [duplicate]

Possible Duplicate: Finding the process that is using a certain port in Linux Suppose I run some daemon but I didn't remember which port it usually use. How can I obtain this information?
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3answers
1k views

how to prevent brute force attack on ssh?

i am running centos. how can i best avoid a brute force attack on my ssh server? I found this list: DenyHosts is a Python based security tool for SSH servers. It is intended to prevent brute force ...
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2answers
2k views

Is Mac OS X a UNIX-based OS? [duplicate]

Is OS X Mountain Lion a pure UNIX-based OS? Some tutorials say that it is a Unix-like OS, but after version 10.5, all Mac operating systems are based on pure UNIX. Is this true?
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1answer
379 views

What is a child process?

I have an error in my error logs that I am trying to figure out but I don't know what to be looking for when it says Child Process. I understand that its a process done by a parent, but that's an ...
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1answer
96 views

Recommended permissions for /home

What is a recommended setup for /home permissions? I know about user / group / other, about sgid flag and I know what User Private Groups are. I have read the comment about adduser no longer setting ...
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3answers
279 views

Replacing quotes in a file

I have a large number of large semicolon-separated data files. All string fields are surrounded by double quotes. In some of the files, there are extra quotes in the string fields, which messes up the ...
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1answer
519 views

Unable to run commands with “sudo” from my user

For some reason, I am unable to run any commands with su as my user. This was working before and I'm not sure what broke it. The funny thing is that I can su to root without any problems. Example: ...
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2answers
504 views

command to show number of processors in UNIX

I want to check the number of processors using by a particular process in unix solaris. Which command we can use for that? Thanks, D.
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1answer
741 views

Unable to install finger package in Ubuntu

I am unable to install the finger package in Ubuntu .Below is the output on my terminal when I tried running the command `sudo apt-get install finger` ritesh@ubuntu:~$ sudo apt-get install ...
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1answer
88 views

Python by default on all unix systems? [closed]

There was a discussion on which language to choose for a system checker. The system checker is supposed to be a script running on unix systems. On Gnu/Linux systems seem to always have it installed ...
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2answers
2k views

Can't access Terminal anymore, only shows a cursor

I run OS X. Following these directions (Installing MySQL on Mac OS X) I added a file to /usr and the contents were PATH=/usr/local/mysql/bin:$PATH Actually I was trying to get the mysql command ...
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1answer
369 views

Running cronjob on specfic hours

How do i setup a cronjob to run every hour except from 11pm until 1am ? Because during that time, the system is doing maintenance. Cheers
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2answers
255 views

Combining files in .tar file in Linux

I have a problem with zipping files in .tar file in Linux, but the challange is that when we extract .tar file it shouldn't give us a folder containing files which are zipped . It should give just ...
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1answer
378 views

What are the security implications of doing “chmod a+rx ~/Documents”?

In order to get the Apache in Mac OS X Lion to work with symlinks, I had to follow the instructions on this page: https://discussions.apple.com/thread/1771399?threadID=1771399 One of the things I ...
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3answers
662 views

Password protect /etc/hosts file

Can I create a different permission to access the hosts files so that the sudoer needs this extra key in order to access it? Also, would password protecting the file prevent OS from accessing it ...
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3answers
4k views

How to recover deleted file in mac? [duplicate]

I wanted to copy a file using cp, however, I happened to type rm and the file was deleted. How can I recover it? The file is stored in a mobile hard disk drive with FAT32 file system I'm using Mac ...
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1answer
1k views

Remote Desktop from UNIX to Windows

You know how you can enable x11 forwarding and through putty when you use a program on the remote UNIX machine, the visuals of it (GUI, etc.) appear on your end? What I'm trying to do is instead of ...
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2answers
304 views

Unmount One hard-drive and re-mount it as another directory in Unix

I recently got my first Unix Dedicated Sever running CentOS I just ran df -h and found this: Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup00-LogVol00 ...
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2answers
12k views

how to fix Permission denied on directory in unix?

I have a ksh file which will download a zip file from the internet in the /tmp directory with name f.zip Why do I get Permission denied? $ ./downloadbcfi Current name is ...
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2answers
684 views

egrep: CPU and memory usage

My Linux machine has 16 processors and free memory of 70 GB but when I run an egrep command, the command is using (checked through the top command) 100% of CPU and 0.5 of memory: 22391 aime 25 ...
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1answer
1k views

Unix pipe: find | ln -s

I'm trying to symlink some php files using the following command: find `pwd` -name "*.php" | ln -s * /home/frankv/www/bietroboter.de/symlinks However, all the symlinks are broken because the little ...
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1answer
76 views

How do I grep for foo && !bar?

I want to output all the lines in my source code which contain the string foo but don't contain the string bar. I tried this: find . -name "*.[hc]pp" | xargs grep -n foo | grep -x bar However ...
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1answer
631 views

Linux - real root vs normal root

Is there such a thing as a normal root and a real root in Unix/Linux? I am doing a buffer overflow project (in Ubuntu 11.04) and I invoke /bin/zsh and /bin/bash separately. In both cases $whoami ...
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1answer
4k views

House keeping removing 30+ days old files using shell script

So I have to bit of housekeeping for old backups and have the following code working on sh: find /home/backups -mtime +30 -type f -exec rm -rf {} \; This works fine as know the location/path, so ...
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1answer
157 views

PC vs Mac… why are things this way? [closed]

Why is it that you can run all sorts of operating systems on PCs (such as Linux, Windows, UNIX, BSDs, etc) but can't run Mac OS / Mac OS X? Conversely, why can't you run anything but Mac OS / Mac OS ...
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1answer
149 views

Quickest way to learn the useful terminal commands [closed]

I'm an iPhone developer but surprisingly (even to myself) I am completely unfamiliar with terminal. The only things I know how to do are cd, ls, top, kill and the git commands for setting up ...