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

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1answer
34 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
125 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
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1answer
58 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 ...
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0answers
18 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
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0answers
16 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
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4answers
309 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
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1answer
26 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
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2answers
22 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
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1answer
130 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
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4answers
854 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
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1answer
23 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
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1answer
353 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
155 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
219 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
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3answers
34 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
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0answers
23 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
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1answer
22 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
35 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
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4answers
62 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
57 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
53 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
31 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
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1answer
52 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
38 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
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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
479 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
45 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
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4answers
482 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 ...
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0answers
63 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
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2answers
101 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
39 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 ...
1
vote
1answer
31 views

How do I control output after executing a command?

.. Script Run Complete. You have new mail in /var/spool/mail/<user-name> -bash-3.2$ I have seen the above message most the times on my prompt, probably while it's idle or as soon as script ...
1
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0answers
18 views

mkvmerge Backward Spliting not supported why?

I tried this:- mkvmerge -o new_file.ogg --split parts:0s-104s,+94s-208s,+8s-12s,+312s-410s,+17s-21s 500.ogg Thrown this error: "The start time must be bigger than or equal to the previous part's ...
1
vote
3answers
92 views

What is the meaning of ls -d ?

I entered the man page of ls, the entry for the -d option is as follows: -d, --directory list directory entries instead of contents, and do not derefer‐ ence ...
0
votes
1answer
32 views

tail-ing a filename that is a date [duplicate]

I am creating a logfile from kermit named the current date (which is in the format of DD MMM YYYY - which can not be changed AFAIK), and using the file name as today's date. I then have a Bash script ...
1
vote
1answer
43 views

Replace case-insensitive string in all folder files

I'm trying to replace a string with another in all files in dir. Trying to use this command sed 's/foo/bar/' * But it replaces foo and not fOo or Foo and others. how to find "foo" ...
0
votes
2answers
53 views

Why can't I kill the shell using the PID obtained from the $$ special variable? [duplicate]

After I have learned that the $$ special variable holds the process number of the shell, I tried too kill the shell by simply: kill , however this did not work, I also tried some variations, but them ...
7
votes
7answers
191 views

What is the purpose of having two variables ($@,$*) to transmit the arguments of a command into a script? [duplicate]

I have read of the special variables used in a script $@ and $*. As far as I understand, the arguments used while executing the script are stored into two special variables, once all arguments into $@ ...
1
vote
1answer
52 views

No such directory after creating it

I'm taking a basic Unix course and right now we're learning terminal. My directions are create a directory called company and subdirectories called sales, accounting and marketing. So I did that. ...
0
votes
1answer
74 views

SIPp “hello world” message to Asterisk

How do I run diagnostics against Asterisk? Asterisk is running on tleilax; and doge is on the same network (My network topology isn't optimal). Specifically, I want to do something like: sipp ...
1
vote
1answer
93 views

Changing themes and hot-corner settings from command-line

I want to change the elementary tweak themes and hot-corner settings on my Elementary Luna (built on Ubuntu 12.04 "Precise") from the commandline. With what command can I do this? I know how to make ...
1
vote
1answer
124 views

Linux commands for kids [closed]

My youngest daughter (6) is fascinated with the sl and gti commands. She even learned to combine them with ; and when the time comes to teach her about return values I'll show her how sl && ...
1
vote
1answer
17 views

How to display metainformation for different kinds of time of a file ?

As far as I know each name within a path, e.g. /name1/name2/name3, is allocated to one inode. This inode is a collection of meta information for each name (file or directory). Some of these ...
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votes
1answer
55 views

How to install stardict from a tar.gz manually ?

I have downloaded stardict-2.0.0-pre2.tar.gz and applied the extraction on it by writing: tar xzvf stardict-2.0.0-pre2.tar.gz , thereupon a new folder was created with the following content: From ...
11
votes
5answers
837 views

How do I get the size of a directory on the command line?

I tried to obtain the size of a folder (containing folders and sub folders) by using the ls command with option l. It seems to work for files (ls -l file name), but if I try to get the size of a ...
3
votes
3answers
66 views

how to remove accidentally created '~' and '..'

I'm using wget to download some webpages and I used the -P option without knowing that it wouldn't expend .. or ~. So I found I've created them after running the program. Now the problem is, how do I ...
2
votes
0answers
43 views

How to display entire subject line in `mail`?

There are two messages in /var/mail/test. mail Mail version 8.1.2 01/15/2001. Type ? for help. "/var/mail/test": 2 messages 2 new >N 1 test@test Tue Feb 17 15:07 18/628 *** SECURITY ...
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votes
2answers
55 views

How to create a new partitioning table on SD card from the command line ? [closed]

I have tried to mount a SD card on Linux Mint, I have found the right device file and tried: mount -t vfat /dev/sdb /mnt/zauberportal ,but it failed and I tried some variations like different types of ...
2
votes
2answers
148 views

Using find to list all files under certain directory

I'm trying to use a single line command that will find every directory (or sub-directory) named bin and will then print a list of all the files under it, but will not also list the directory names ...