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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5
votes
2answers
47 views

Merging/Combining 2 text files according to numeric field

I have 2 text files file_1: 14595|Age 35|Salary xx|Position ax|2013|Info 1|Info 2|Info 3|Info 4|Info 5 14649|Age 30|Salary xx|Position az|2015|Info 1|Info 2|Info 3|Info 4|Info 5 file_2: ...
0
votes
1answer
12 views

Linux bash commands in android 4.1.2?

Is there a way to run linux bash commands in android (particularly 4.1.2 rooted or not rooted)? Will it void the warranty from phone manufacturers?
1
vote
3answers
77 views

What does “>” do vs “>>”? [duplicate]

I am currently doing preparation for my GCSE computing controlled assessment on Linux. I type ls > list and ls >> list into the command line, but it does not do anything. I have googled it ...
1
vote
2answers
55 views

The command 'cp' can only used on block device?

According to my last question I think we can't use 'cp' to copy file to the tape device or device like '/dev/lp0'.But I still don't understand why. To make this question simple enough,just tell me if ...
0
votes
1answer
79 views

find - exec rm vs -delete

I'm trying to understand the difference between these two commands: sudo find / -name .DS_Store -delete and sudo find / -name ".DS_Store" -exec rm {} \; I noticed that the execmethod is ...
0
votes
1answer
22 views

What is the command to check what version of Java ME I have installed?

I have Debian 6 installed on a device and want to check what version of Java ME I have installed. I tried java -version, but I get -sh: java: not found. What command should I use?
0
votes
0answers
26 views

How do I force a command to be run on local login?

I was wondering how do I force a command on login of a linux system? (debian 7). This is for a 2FA authentication command. I am asking for a local login.. not ssh.
1
vote
1answer
55 views

Get two values from command output in a bash script

I have a bashscript, which executes a command and calculates a pair of values, which output can look like this. a,b (10.0000000000, 10.0000000000) -> volt (2088133.7088034691, -222653.3238934391) ...
2
votes
1answer
60 views

Convert all non-JPG images to JPGs

What command can I use to convert all images in a folder which are not JPGs (PNG and BMP primarily) to JPG? I'd also like the conversion quality to be 100%. And I'd like the converted images to ...
25
votes
20answers
6k views

How do I print pi (3.14159)? [closed]

What command could print pi for me? I want to specify how many digits it prints, I couldn't find anything online. I just want to be able to print pi.
2
votes
2answers
33 views

Is there a `--paranoid` type flag for common, potentially irreversible commands?

I'm not aware of any standard flag that is implemented. There are some git commands that let you specify a -n parameter that will show you what the command is going to do, but doesn't actually do it. ...
1
vote
1answer
31 views

Checking permission for files

Is there any way to check/find files and directories that only I created and check their permission?
-2
votes
1answer
36 views

Sorting by size

When I run ls | sort -S I get sort : option requires an argument -- ´S´ Why I cant sort the list of my files with the sort option by size? I know that I can use only the ls command alone. ...
1
vote
3answers
32 views

Command that passes its input through to output AND performs command?

I'm trying to use the quote program to make a little shell script that'll keep updating the stock prices every second. quote has to access the Internet and therefore has a small delay when it runs. I ...
1
vote
1answer
34 views

What is the name of the app displaying custom text in fullscreen size?

I have seen years ago a very handy application: the command displayed it's first argument enlarged to fit the whole screen. For example... thiscommand AA ...then you could see two very big A ...
2
votes
2answers
79 views

What filesystem mount point am I currently working on?

I would like to know in what filesystem mount point I am currently on, similarly to using pwd to know what directory I am in. I know you can use df . (or df $(pwd) or many variants), but I find it ...
1
vote
2answers
52 views

Find average CPU, vMem, sMem usage on 1, 5, and 15min

I am trying to find at time T the average CPU usage on 1, 5, and 15min, just like what you get from /proc/loadavg Same thing for virtual memory, and swap memory. I would be fine with a python ...
8
votes
2answers
428 views

Finding a file type assuming wrong extension

I have an image archive I keep up. Sometimes, the sites I pull them from reformat the file while keeping the extension the same, most often making PNG images into JPG's that are still named ".png". ...
0
votes
2answers
172 views

What are the meanings of different Unix commands? [closed]

I am running Ubuntu 14.04 on my machine. I am new to Linux and feeling lost when I see different command line commands (or what exactly are they called?) like sudo, apt-get, mkdir, -R, -n etc. while ...
1
vote
2answers
45 views

Replace text/string with new line

I have had a requirement where I need to move data to a new line based on a text: Input :61: 456 B66666 :61: 878 N78777 :61: 534533534 BNNN Output :61: 456 B66666 :61: 878 N78777 :61: 534533534 BNNN ...
0
votes
4answers
52 views

How to save in a variable the convert from decimal to binary without use an echo

I've been trying to save in a variable the value of the convert of a number from decimal to binary, like this: num1=10 echo "obase=2;$num1" | bc | tee -a register.txt but I don't want to show it ...
1
vote
1answer
38 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?
3
votes
2answers
142 views

How to use getopt in bash command line with only long options?

There is a getopt command in bash command line. getopt can used with short options (such as getopt -o axby "$@"), and can be used with both short and long options (such as getopt -o axby -l long-key ...
-8
votes
2answers
52 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
112 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
55 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.
-2
votes
1answer
203 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
27 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?
0
votes
0answers
26 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 ...
1
vote
2answers
82 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 ...
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
3answers
80 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
59 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
53 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 ...
1
vote
0answers
33 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: ...
2
votes
1answer
48 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 ?
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!
0
votes
2answers
53 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
159 views

What is $() in a command?

What is $() in Linux Shell Commands? For example: chmod 777 $(pwd)
1
vote
3answers
231 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
5k 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
59 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 ...
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 ...
1
vote
0answers
169 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
26 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
58 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 ...
3
votes
4answers
955 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, ...
30
votes
5answers
813 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 ...
0
votes
1answer
51 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
95 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: ...