One or a set of directives issued in the *nix environment to get information, change the state of something or to execute something. In other words: To gain an objective.

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1
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1answer
32 views

Execute commands when specific user and ip login to ssh

How can I execute a few commands when a specific user with a specific IP logs on via ssh?
0
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0answers
20 views

My Ubuntu won't recognize the command ./configure [on hold]

I have recently purchased a computer off of my sister that she wiped and loaded with Linux. Now that I have it, I have no idea what I'm doing and need some help. I have been trying to install Unity ...
6
votes
3answers
2k views

Difference between 'ifconfig' and 'ip' commands

I read some articles/tutorials on 'ifconfig' command, most of them included a common statement - "ifconfig is deprecated by ip command" and suggested to learn ip command. But none of them ...
4
votes
2answers
3k views

How to see the total progress while copying the files

We know that if we give --progress parameter to rsync it will show the progress of files copied. But issue is that is shows the progress for each single file not total or overall progress. So how to ...
-8
votes
2answers
45 views

How to create my arbitary output? [closed]

How can I write a shell script that give me following output: Today is: Thursday, November 05, 2014 The IP for localhost.localdomain is: 192.168.141.140
1
vote
1answer
67 views

Why is variable assignment preceding command ignored? [duplicate]

The bash 4.1 manpage states (emphasis added)... Simple Commands A simple command is a sequence of optional variable assignments followed by blank-separated words and redirections, and ...
0
votes
1answer
40 views

From Terminal, how would I copy a text file from the desktop into a USB?

I'm just trying to repeat command line basics.
6
votes
2answers
390 views

what is the meaning of this sed command: `;/@/{h;s/test/next/g;x;G}`?

sed -e 's/72;/72, next_val = 0x11111111;/;/@/{h;s/test/next/g;x;G}' fmt_vuln.c > fmt_vuln2.c could you tell me about what is the meaning of ;/@/{h;s/test/next/g;x;G}?
5
votes
1answer
394 views

What exactly are commands? How to identify? [duplicate]

I want to know what exactly are Linux commands? & how to identify and locate them? (Say Introduce the "commands") In other words what are different kind/type/category of commands? How to identify ...
-2
votes
1answer
80 views

Delete all mails from inbox using linux command prompt

How can I delete emails from an individual email account? e.g. how can I empty userxyz@mydomain.com? I know the following: /var/spool/mail/mydomain /var/mail/mydomain I have many inboxes some of ...
1
vote
1answer
21 views

What does the parenthesis mean in a command description like “mklost+found(8)” [duplicate]

When googling for linux commands, I often see a number in parenthesis like this: mklost+found(8) What does it mean? Is it a version number of the program, reference to some standard, or what?
11
votes
5answers
29k views

How to move all files and folders via mv command

How can I move all files and folders from one directory to another via mv command?
0
votes
0answers
25 views

want to replace a file data from another file [duplicate]

I want to replace a file data from another file Suppose file1 have data written below and file2 have some data i want to store replace file1 data from file2 from starting word // +++ CUSTOMIZATION ...
19
votes
4answers
1k views

The difference between -r and -R

It often happens that I want to apply an operation recursively. Some commands, such as grep, use a lowercase r to indicate recursion. For example grep -r foo . Other commands seem to prefer an ...
1
vote
2answers
69 views

How to kill all processes for a given user that take longer then X time

When I list processes with ps auxf I often see some that are stuck and I need to manually kill them. How can I do it with one command? Example ps result: $ ps auxf USER PID %CPU %MEM VSZ ...
1
vote
3answers
71 views

What is the concept hidden behind the term “command”?

I have been using, studying and developing for Linux for quite a few years now, and over time, I have successfully convinced a few people to join the cause, and make the switch to Linux. However, ...
2
votes
1answer
41 views

Command to print few consecutive lines from middle of a file [duplicate]

For a file containing 20 lines, lines 6-10 can be printed using following command: head -10 filename | tail -5 Can this exactly same thing be done without using 'head' and 'tail' commands ?? ...
0
votes
2answers
43 views

execute command from txt file

I have file and in this file i have this lines: ssh root@server1.com ssh root@server2.com etc.... And i have script that i like to go on every server and execute the ls command on each of this ...
2
votes
1answer
67 views

How to convert .doc to ODF with a command line?

I'd like to convert many Microsoft Word documents to ODF (the OO.org formata with a command line (because there are many of them). (I need them for reading afterwards on a device where reading OO.org ...
1
vote
0answers
32 views

Edit a command? [duplicate]

I'm using many basic commands of unix/linux. In Mac OS X Mavericks, I type cat for a file, but output was faulty. In example, content of the file named bar: foo bar Then: ...
5
votes
1answer
165 views

What does `init [2]` mean in the COMMAND column of ps?

Reading What do the brackets around processes mean? I understand that the executable name is printed. Linux ps man page: Sometimes the process args will be unavailable; when this happens, ps will ...
9
votes
6answers
1k views

How do you remember command options? [closed]

I am curious to know what trick you use to remember options for various commands? Looking up man pages all the time is time consuming and not so cool!
4
votes
5answers
93 views

unix command to print till 3rd occurence of “/” in each line

I have one file contains data as follows... /tutordashboard/manageTutorLogInStatus/?ua=TQ-AUTOCLOSE-REENTER&filterId=089089087087080&dt=1325757272 ...
2
votes
1answer
46 views

What is a command that will only show me the command syntax and options?

Is there a command which will just list all the options for a given command on one or two lines and not as long and words as man or info ?
0
votes
2answers
41 views

`cron` service and `at` command

Help to understand: is there any relation between cron and at command. Actually if I stop the cron services in SUSE by running following command: /etc/init.d/cron stop after above, if I run at ...
1
vote
3answers
155 views

What is $() in a command?

What is $() in Linux Shell Commands? For example: chmod 777 $(pwd)
85
votes
3answers
8k views

Why is “echo” so much faster than “touch”?

I'm trying to update the timestamp to the current time on all of the xml files in my directory (recursively). I'm using Mac OSX 10.8.5. On about 300,000 files, the following echo command takes 10 ...
6
votes
4answers
2k views

In UNIX, how to find the most commonly used commands in history of unix?

In UNIX, how to find the most commonly used commands in history?
1
vote
3answers
127 views

How to rename file using substring of the same file name [duplicate]

I want to rename my file with its substring.Because unfortunately renamed all the files in my server. Now I want to remove suffix( .gz) of all the files including files in subdirectories also. Below ...
4
votes
1answer
2k views

ifconfig command not found

I've just installed CentOS7 as a virtual machine on my mac (osx10.9.3 + virtualbox) .Running ifconfig returns command not found. Also running sudo /sbin/ifconfig returns commmand not found. I am root. ...
1
vote
0answers
55 views

alias Not able to execute source command

I am trying to define a following alias in my .aliases file. alias sett 'cleartool setview viewXYZ_!*; cd /path_dir1/dir2/; source ./env/script-name' I use it as sett myview on commnd prompt when I ...
1
vote
0answers
132 views

ssh from an unix server to a windows server (running Sysax) fails

We are doing a sFTP from an Unix server to a Windows server and also a ssh, from the Unix server to the Windows server, to execute a file present on the Windows server. These 2 steps worked well. ...
3
votes
1answer
40 views

Switching users without the - symbol

I had to switch to a different user earlier for something that I was working on. I have originally done: su support While I was successfully able to switch to support, I found I was unable to make ...
3
votes
1answer
23 views

How to execute as the logged-in user in a sudo script (OSX)?

Is there a way to switch contexts like that? The script in my specific case is an installer postinstall script, which requires sudo privileges only for some of the tasks and requires the logged-in ...
4
votes
1answer
48 views

How to update 'command cache' after change of soft links?

I have changed multiple soft links on my system with ln -f -s. When I view the link with ls -l, I see they point to the right target. However, when I try to run the command, it still tries to use the ...
29
votes
5answers
764 views

How to save a command you entered without executing it? [duplicate]

Every Linux user has experienced this annoying thing: you begin typing a long and boring command, then realise you should have executed another one before. How to save the first one to execute it ...
3
votes
4answers
187 views

Generate random numbers in specific range

After googling a bit I couldn't find a simple way to generate with a shell command a random number included in a specific range, between a minimum and a maximum. I read about /dev/random, ...
0
votes
1answer
48 views

How to save mails in Unix? [closed]

I wanted to save mail in unix in some directory, as we do in outlook (files are saved with .msg extensions). Is there any workaround for doing this.
1
vote
1answer
62 views

Multiple MODULEPATH entries in .modulesbeginenv

I'm switching between paths/code projects. At each place I have different modules. To handle this there is a setup script that modifies what to use. This is handled with the tool 'module'. NOTE: ...
22
votes
4answers
1k views

Is the shell permitted to optimize out useless terminating commands?

If a shell is asked to perform a probably useless (or partially useless) command known to terminate, such as cat hugeregularfile.txt > /dev/null, can it skip that command's execution (or execute a ...
8
votes
3answers
404 views

Vim: pasting lines line by line

Let's suppose I have a file containing: xxx yyy zzz and another file: kkk qqq ppp I want to obtain: xxxkkk yyyqqq zzzppp Is that possible in Vim with some command? (I've tried using VISUAL ...
3
votes
1answer
42 views

Printing short latex snippets

Is there a way to quickly (render and) print short latex snippets like single equations? Something similar to echo "Some text" | lpr like make-latex-image "$\frac{some}{equation}$" | ...
6
votes
1answer
241 views

What's the difference between “realpath” and “readlink -f”

I've read a lot about realpath command and how it has been deprecated with the readlink -f being now recommended. I have also seen in some places that the reason why realpath was introduced was for ...
7
votes
3answers
1k views

Difference between sudo -i and sudo su [duplicate]

I was wondering what the difference is between sudo -i and sudo su?
3
votes
1answer
4k views

Does Linux allow executing the “rm -rf / ” command? [closed]

We all know that we have to use the -rf option of rm command carefully. What I wonder is does Linux allow executing this command: rm -rf /? If so, why? This command could have disastrous ...
7
votes
2answers
298 views

Change the order of executables started in bash

If I execute the test command in bash, test(evaluates conditional expression) built-in utility is started: $ type test test is a shell builtin $ type -a test test is a shell builtin test is ...
1
vote
4answers
234 views

List all commands that a shell knows

What can I type at my shell (which happens to be bash) that will list all the commands that are recognized? Also, does this differ by shell? Or do all shells just have a "directory" of commands they ...
6
votes
4answers
131 views

Is there a tool for summarizing what all commands do?

So I understand that there are man pages for getting the documentation when the internet is unavailable, or when you need advanced uses, but what if I'm offline and I don't even know what tool I need ...
2
votes
2answers
176 views

Tool for viewing top N items in stream

I'm looking for an existing Linux command-line tools that can accomplish the following: Consider there is an input stream /dev/inputstream which spews an infinite stream of data that looks like this: ...
0
votes
3answers
5k views

What is the difference between ps and top command?

What is the difference between ps and top command ? I see that both can display information about running processes . Which one should be used when ?