The command-line is the interactive interface to your shell.

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5
votes
3answers
465 views

How to put a newline special character into a file using the echo command and redirection operator?

I would like to create a file by using the echo command and the redirection operator, the file should be made of a few lines. I tried to include a newline by "\n" inside the string: echo "first ...
0
votes
0answers
48 views

Dropped connections with b43 driver using Broadcom BCM43228 wireless chip on Arch Linux

I managed to get my wireless working with the b43-firmware package in the AUR and for at least a month it worked perfectly. However, recently the internet connection has been dropping out. I'm ...
1
vote
2answers
45 views

Open Firefox twice (with same profile)

There are tons of resources that tell how to run several instances of Firefox in parrallel. I can't find any that tells me how to configure a command (on a command line, start menu item, or panel ...
0
votes
1answer
26 views

. as a command line argument to a command running in background

I run grep some-string -r . &. While it is running in bkg, I cd to another directory. It seems that grep interprets the hard link . differently then. What happens before and after I change the ...
1
vote
1answer
102 views

How to Prompt the user to press Enter to Exit in terminal so that the terminal doesn't close automatically?

Here is my Port.sh file echo 'Give me a maximum of 5 seconds to run please.' lsof -i | grep Xvnc | grep ESTABLISHED | grep $USER lsof -i | grep $USER | grep Xvnc | grep -o -P '(?<=:).*(?=->)' ...
2
votes
1answer
23 views

How to determine the only additional file in otherwise two identical listings?

I have done a listing of the device folder two times, one time without the sd-card in the slot and one time inserted, the system automatically adds one file in the device folder. $ ls /dev | wc -l ...
3
votes
2answers
266 views

How to Find UID, GID, and any groups I belong to?

How to Find UID, GID, and any groups I belong to ?
5
votes
2answers
234 views

How to count duplicated last columns without removing them?

I have a file that contains 4 columns. I want to compare the last three columns and count how many times they occur without deleting any of the lines. I just want the count to be present in front of ...
1
vote
2answers
48 views

Live resizing of an ext3 filesytem on CentOS6.5

I have a problem with my remote server hosted by my provider, I have only SSH access. The problem consist of getting this error file system rootfs has reached critical status that causes problems with ...
1
vote
0answers
34 views

Printing to the terminal after boot

I am attempting to start a script that echos to the terminal once matchbox-terminal is loaded. I am able to run the script if I execute it in the existing xsession script located in ...
1
vote
1answer
75 views

awk with variables in condition and in output redirection file

I would please like some help with this command because I didn't find anything in documentation that can cover everything I want. I have some variables that are global, so I would prefer to keep them ...
2
votes
1answer
31 views

Is there a command that outputs ONLY the packages explicitly installed by the user? (ubuntu/debian)

I have tried searching for this but there seems to be no command that can output a list of packages (ideally in Ubuntu) that I have installed, not including any dependencies.
0
votes
1answer
34 views

unable to remove stopped job with ctrl+c

When I tried to change from super user to common user and therefore typed "exit", I got an error message, that a job was stopped and I could not log out as root. So I listed the jobs: #jobs [1]+ yes ...
12
votes
3answers
446 views

How can I make a graphical plot of a sequence of numbers from the standard input?

If have a long text file and I want to display all the lines in which a given pattern occurs, I do: grep -n form innsmouth.txt | cut -d : -f1 Now, I have a sequence of numbers (one number per line) ...
2
votes
2answers
262 views

Is it possible to login as root without the interactive password query ?

When I want to login as root, I usually have to type: su -l and than an interactive query starts in order to receive the password. Is it possible to login as root without this interactive query ? ...
0
votes
1answer
55 views

How can I observe my own actions via terminal

To understand Linux better I want to see which commands run in background. For example when I create new file via GUI, is there any way to see the which command runs in terminal?
0
votes
0answers
19 views

How to read - in Linux? [duplicate]

Whenever I am dictating linux CLI commands to someone I get in a dilemma on how to say - in English. For example, to dictate ls -la I sometimes say L S minus L A or L S hyphen L A or L S dash L A. Is ...
3
votes
2answers
145 views

How do you stop a bash shell expansion?

I know some methods for stopping process. When I type: echo {1..999999} > filename.txt I can't stop it from running. I can stop other processes with Ctrl+C | Ctrl+D | Ctrl+\ and etc. But none ...
1
vote
1answer
43 views

Why do my run level directories contain only start scripts and no single kill script?

I learned here that for each runlevel exist a directory with start and kill scripts. The start scripts are activated on entering , the kill scripts on leaving the runlevel. Start scripts and kill ...
2
votes
4answers
187 views

Creating directories in a loop and moving files to those directories

Consider a directory with N files. I can list the files alphabetically sorted and store the list by ls > list Then I want to create n sub-directories in same directory, which can be done by ...
3
votes
1answer
70 views

rlwrap -z pipeto: piping output through pagers

I am using rlwrap to colorize prompt in asterisk CLI: rlwrap -s 99999 -a -pRED /usr/sbin/asterisk -r I read in man rlwrap that I can also use rlwrap -z pipeto to pipe output through a ...
1
vote
0answers
24 views

How to start the twm manager on a system which already has a window manager ?

I am using linux mint codename rebecca with xface. I tried to follow a description how to start a window manager of once choice: created an empty .xinitrc file in my homefolder filled the file with ...
0
votes
0answers
28 views

How to install a particular version of boost with brew on MacOSX?

The command "brew install boost" works for me on my MacOSX, but it installs the latest boost 1.57. How to use brew to install the older 1.55?
2
votes
4answers
348 views

What is the difference between (cp f1.txt f2.txt) & (less f1.txt > f2.txt) [duplicate]

I know that both will copy data from f1.txt to f2.txt, but what is the real difference? (cp f1.txt f2.txt) vs: (less f1.txt > f2.txt)
0
votes
1answer
28 views

How can I expand a terminal using the command line? [duplicate]

When I start the terminal in my xfce Destop environment a black winodw about a quarter of the screen size appears, if I want to expand it to full screen size I have to click on the "+"-shaped symbol ...
1
vote
2answers
24 views

Transform values in a line by first field

I was wondering if there is an easy way to do the following without writing a script. Transform 1234,"a;b;d" 2345,"e;f;g;h" to 1234,a 1234,b 1234,d 2345,e 2345,f 2345,g 2345,h
1
vote
1answer
144 views

Operate X clipboard from command line

I'd like to copy and paste to the clipboard from the command line. I've found two utilities that works with "mouse" selection: xclip and xsel. But they both ignore the clipboard that is filled with ...
20
votes
4answers
879 views

Is it possible to redirect the output of a command into more than one command?

As far as I know, I can use the tee command to split the standard output onto the screen and further files: command -option1 -option2 argument | tee file1 file2 file3 Is it possible to redirect ...
2
votes
1answer
24 views

Sandbox an account and prevent it from any system modifications

I am trying to sandbox a user account to the point where it cannot edit or view any files beyond a certain folder, namely /home/user/test. This account will be compiling and running a C++ program that ...
9
votes
1answer
428 views

Why does the echo command do not work with at command?

when I type: at now + 1 min at>play /usr/share/sounds/startrek.wav at>ctrl+d it works, so after one minute there is actually a sound played. but, when I type: at now + 1 min at>echo ...
0
votes
1answer
163 views

extract number of bytes out of a file

Is it possible to extract a few number of bytes out of a file using dd ? The file is located on a secondary drive. I apologize if this is a simple question however I'm no pro at command line.
0
votes
1answer
242 views

Replacing white-space / characters with backslashes [duplicate]

I want to convert a bunch of mkvs to mp4s with the following command: for i in $(ls *mkv); do ffmpeg -i $i -vcodec copy -acodec copy $i.mp4; done; However, the filenames have whitespaces and ...
0
votes
3answers
42 views

Why do du's subdirectory values not sum up to total?

I'm trying to use du to investigate disk usage in a directory like so: du -hd1 | sort -rh This gives me a list that starts as follows 61G . 7.9G ./A 5.1G ./B 2.7G ./.C 1.6G ./.D ...
1
vote
0answers
32 views

Check if there is no GUI

Is it possible to check if a UNIX machine (Mac / Linux) has a GUI? Basically I would like to distinguish between: UNIXes with GUI (i.e. normal Macs, Linuxs) UNIXes with no GUI (i.e. Mac server/ ...
0
votes
1answer
23 views

How to switch from input mode into command mode in ed ?

As far as I know, ed starts in command mode. Once I input i,a or c ed changes into input mode. So far it worked. Now I read that in order to switch from input mode into command mode one has to input ...
2
votes
1answer
55 views

How can I redirect output files to a specific directory/folder

Suppose I have an executable in Unix. Suppose the name of the .exe file is myExe and it takes two parameters. I did not create this executable, this is a freely available one. myExe generates 4 ...
0
votes
4answers
88 views

How does “-dc” work in “cat /dev/urandom | tr -dc ”01"?

So far I know, the /dev/urandom file is one of the special files, it's purpose is to generate random characters. When I execute cat /dev/urandom a stream of strange characters, some even Chinese ...
0
votes
2answers
63 views

Why would the prompt get overwritten?

p_ash-3.2$ cp some_file1234.html /some/loc/ation/ofthe/some_file1234.html.html_Backu Have been seeing this intermittent issue with the command-line, while typing longer lines as part of any command, ...
0
votes
2answers
57 views

use `mv` command and my file gone [closed]

i want to move myfile.tar.gz to folder My command is mkdir backup mv myfile.tar.gz /backup arrrgh, and the file gone in /backup directory not exist, try using find command not shown how to ...
3
votes
0answers
39 views

Convention/standard on using curly braces around options

Man page for tar in arch linux SYNOPSIS section starts with: tar {A|c|d|r|t|u|x}[GnSkUWOmpsMBiajJzZhPlRvwo] [ARG...] I perfectly understand that in this situation it means that exactly one of them ...
1
vote
1answer
57 views

cd to my folders shows me an error

I just logged out my system and logged on. And i tried to get into my folder cd /u/folder It says Too many levels of symbolic links. But it worked yesterday. What could be the reason? I found ...
0
votes
1answer
62 views

ssh-copy-id different port

i am trying execute ssh-copy-id in one port different than 22 (default). I researched and found the command below $ssh-copy-id -i ~/.ssh/id_rsa.pub "user@192.168.0.1 -p 22001" but, when execute the ...
10
votes
7answers
2k views

Is it possible to reverse a command in the bash shell?

I was wondering if there is a (simple) possibility to redo/reverse a command that was executed in the bash shell? (to make it undone) Is there something similar to the ctrl+z combination to redo any ...
3
votes
3answers
502 views

Why do we have to pass the file name twice in exec functions?

I read Advanced Programming in the UNIX Environment by Stevens, 8th chapter. I read and understand all the six of exec functions. One thing I notice is, in all the exec functions: first argument is ...
0
votes
1answer
66 views

Saving from arecord on a raspberry pi across a network to a mac

I've currently got a usb mic plugged into a Raspberry Pi B+ and am using the following code to record data: arecord --buffer-time=5000000 -D plughw:1,0 -f cd -t raw | lame -r - stream.mp3 I then ...
9
votes
4answers
520 views

How to remove duplicate characters?

If I am having a line as: Thhiisss iisss mmyyy nameeee I want to print this as: This is my name What is the unix command for this?
0
votes
1answer
29 views

Why aren't sda3 and sda4 displayed with fdsik -l?

I wanted to display all my partitions, so I entered "fdisk -l". AFAIK, the format of the device file for a scsi hard disk reads like: sd_whichharddisk_whichpartition. To my surprise, after hitting ...
1
vote
0answers
66 views

What is the meaning of the string **/* when used with grep?

I came across this picture (below), obviously it is a pun or some kind of allusion incorporating command-line expressions. Frankly speaking I do not understand anything of it except for grep -n. ...
1
vote
2answers
111 views

for loop when matching both front and back of file name

I'm trying to set up a for loop to run a process on pairs of files. The names of the files look like this 36_002_CGATGT_L001_R1_005.fastq.gz 36_002_CGATGT_L001_R2_005.fastq.gz ...
0
votes
1answer
42 views

What is the meaning of (^| )ABC( |$) as an extended REGEX ?

I came here across the command grep -E '(^| )ABC( |$)' file1 I am confused how to interpret the regular expression therein, because I know the ^ and $ character as beginning and end signifier, but in ...