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

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1
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5answers
3k views

How can I output the difference between 2 files?

My file consists of the the following; roughly: username:username:username:username:username The above line continues to about 600 characters. I use the awk command in order to use it as an ...
8
votes
1answer
3k views

Command-line mv exclusion list

Is there a way to mv,cp, or any file operation such that I could specify all the files I don't want affected? For example, say I have a folder with the files file1, file2, and file3, and I want to ...
1
vote
1answer
52 views

Is it possible to establish a Socket session (between Server and Client) using shell commands ?

From what I read (only the very outline, i do not know C Language) a Socket session is established between a server and a client by calling functions for both of them in a certain order. It starts ...
7
votes
1answer
326 views

In which situations are PS2, PS3, PS4 used as the prompt?

When I log on into the shell I see the prompt whose value is stored in PS1. I also encountereded another prompt (but do not know which one) when I used the here-document syntax: bc << HERE ...
3
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5answers
335 views

How to grep the n-th substring between given delimiters?

Let's say we have a string and its delimiter is ?: Leslie Cheung April 1 ? Elvis August 16 ? Leonard Nimoy February 27 I know how to grep the first substring between delimiters: echo $above_string ...
2
votes
2answers
41 views

Is it possible to change the PS1 periodically by a script in the background?

I just came across the PS1 variable (so I am far from being an expert). It is possible to change the prompt by simply changing this variables value, for instance: PS1="\h" hostname as Prompt PS1="\j" ...
1
vote
2answers
50 views

Can not evoke watch command with non-integer time option

I want to start the w command periodically, according to man watch the smallest possible time interval is 0.1. I tried: watch -n1 w (works) watch -n1.5 w (does not work) watch -n0.1 w ...
4
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3answers
178 views

Get last part of string after hyphen

Is there a simple command line to extract the last part of a string separated by hyphens? E.g., I want to extract 123 from foo-bar-123.
3
votes
2answers
155 views

tail display whole file and then only changes [duplicate]

My Linux version is 2.6.32-47-server (gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5.1) ) #109-Ubuntu SMP Tue May 7 02:17:05 UTC 2013 I am currently doing a tail -f file and life is good. But that only ...
16
votes
4answers
601 views

How can I implement a circular flow of data among interconnected commands?

I know of two types how commands can be connected with each other: by using a Pipe (putting std-output into std-input of the next command). by using a Tee (splice the output into many ...
2
votes
2answers
67 views

How can I select and copy file names in the command line without using the mouse?

Typically, when I want to perform an action on a file I discovered in the terminal after calling [ls], I would have to - with my mouse - highlight, left click, copy file name, type the command in then ...
2
votes
1answer
56 views

Need to press enter to get prompt after executing udev script

I have set a simple udev rule for my Raspberry Pi (Debian) to automatically mount an USB HDD. It just runs a script which mounts all devices in /etc/fstab since it's the only one I have and I'm going ...
2
votes
6answers
7k views

How do I set time and date from the Internet?

How do I retrieve the date from the Internet and set my computer's clock, from the command line?
0
votes
1answer
71 views

How can I translate in the CLI an English word into a German one?

I want to write a Script that picks a random English word from /usr/share/dict/words, translates it into German, display both of them for a certain amount of time and repeat the process. I only know ...
3
votes
0answers
54 views

Bash: “history number” vs “command number”

While Googling how to customize my shell prompt via the PS1 variable, I'm seeing tables of special characters that can be used. In particular: \! the history number of this command ...
2
votes
4answers
149 views

How can I create new shell commands?

I'm using bash, and I want to be able to execute a script just by typing its name as a command, same as pwd for example. Is there a specific directory where I need to save my script to, or any other ...
5
votes
1answer
354 views

How to copy a file several times into randomly choosen paths within the filesystem?

I have a filesystem and a special file foo. I would like the script to choose several times (5,10 or 100) random paths to folders within this filesystem and to copy the file foo into each of them. ...
1
vote
1answer
39 views

How to exclude the folders proc and sys from search with find command ?

I wanted to execute a script that picks out a random directory path: find / -type d | shuf -n1 Unfortunately I get error messages about the prohibition of entering certain directories. How can I ...
4
votes
1answer
90 views

How to perform the watch command onto expression with pipes?

I learned today the wonderful shuf command: ls | shuf shows me a listing of the working direcotry, but thanks to shuf each time I execute this piped command expression with another order. So I ...
1
vote
2answers
55 views

pipe in shell with redirection

My understanding is that a pipe in shell like a | b redirects b's stdin to a's stdout. However, I tried ls | less < somefile, the behavior is very strange. less shows the output of ls concatenated ...
0
votes
0answers
39 views

How do I realize a Shell Script that keeps track of how long the keyboard has not been used ?

Is it possible to write a script that counts the time between two pressed keys, so that one could put a script into the crontab that checks if the keyboard had not been for longer than a certain time ...
5
votes
2answers
167 views

How can I list files of which no symlinks exist?

I have a large "myfiles"directory full of miscellanous documents and do not want to modify its structure. I therefore created (several) other directories for each class of documents. For example I ...
0
votes
1answer
24 views

Error I get when I try install IDE Anjuta

sudo apt-get install anjuta Error I get while installing the IDE. What is this error about? However, I am able to successfully install the IDE Unknown media type in type 'all/all' Unknown media ...
2
votes
1answer
83 views

sudo -i returns an error [closed]

When I try to switch to root using sudo -i i get the error /var/tmp/sclDvf3Vx: line 8: -i: command not found... However, su - works which I will continue to use. I'm by no means a linux system ...
0
votes
1answer
56 views

Imagemagick mogrify with shadow geometry

How can I specify the size of a shadow with imagemagick? This command works: montage foo.jpg bar.jpg foobar.jpg -background lightgray -geometry 1031x1642+57+57 -shadow -monitor -tile 3x1 out.png ...
0
votes
1answer
41 views

How can I save the result of a continuous command?

I am trying to append the result of airodump-ng mon0 to a file. I want to run it once, append, and exit. I can repeat the command each x minutes with sleep and so.
2
votes
0answers
28 views

Why reading from and writing to framebuffer shows no effect ?

I read a very short description of how to make a Screenshot by making use of the file which represents the framebuffer /dev/fb0. in order to write the screen content: cat /dev/fb0 > file in ...
1
vote
2answers
61 views

How to list only the last line of each directory?

I learned thanks to you, how to display only the last line of a listing,e.g. ls -ltr | sed '$!d' Now I thought, how to combine it with the find command, in order to repeat this onto each directory ...
1
vote
1answer
60 views

What is the meaning of read -r ?

in order to understand another answer: find / -type d -print0 | while read -r -d ''; do ls -ltr "$dir" | sed '$!d' the first step is to understand the usage of the option -r of the read command. ...
3
votes
1answer
56 views

How to convert all odt files in a folder into microsoft word files ?

I have a folder with a lot of odt files from LibreOffice, I could open each one by hand and save it as a microsoft word file, but that would take a long time, is it possible to reach this goal using ...
1
vote
0answers
32 views

Why won't my python scripts run without the python command when moved from Windows to Linux? [duplicate]

I have some Python files that I wrote on my Windows PC and then sent over to a Linux machine using pscp. They work as intended on Windows, but when I try to execute them on the Linux machine, I always ...
2
votes
4answers
67 views

input file stream to command

How is it possible to send a file stream to this command instead of a file? /usr/local/bin/wkhtmltopdf --title "$SUBJECT" -q $SOURCEFILE $OUTPUTFILE The file stream is from a string in PHP.
0
votes
3answers
41 views

How to display only the last line of a listing ?

Supposed I make a listing and sort the files by its temporal attribute: ls -ltr -rwxrwxrwx 1 bla bla 4096 Feb 01 20:10 foo1 -rwxrwxrwx 1 bla bla 4096 Feb 01 20:12 foo2 . . . -rwxrwxrwx 1 bla bla ...
1
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0answers
7 views

Is it possible to make a key word search of all existing channels of all the irc networks from the command line ?

I am new to IRC (internet relay chat), as I understand it, an IRC network has a unique name like DALnet, is made of a chain of servers, a person can connect to one of them in order to connect to the ...
48
votes
5answers
68k views

ssh-add complains: Could not open a connection to your authentication agent

I've been trying to get ssh-add working on a RaspberryPi running Raspbian. I can start ssh-agent, when I do it gives the following output into the terminal: ...
0
votes
4answers
146 views

Applying different permissions to files vs. directories

Sunny answered the question above in this post, The answer was given as No need for scripts. // Directories: find . -type d -exec chmod XXX {} \; // Files: find . -type f -exec chmod ...
-3
votes
1answer
267 views
0
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1answer
282 views

How to find all JPG files on the file system when .jpg extension is not obligatory ? [duplicate]

First thing I noticed when switched from Windows to Linux was, that Linux has no strict naming convention and no obligatory file name extensions like .bmp, .jpg, .exe etc. Therefore I can not tell by ...
0
votes
1answer
302 views

What is the command-line equivalent to 'mintupdate' for Linux Mint?

Linux Mint has a nice GUI-based Update Manager with selectable update tiers. The defaults are for levels 1 through 3 our of a possible 5 levels. However, I often handle administrative tasks for a ...
1
vote
2answers
866 views

An alternative to `xdotool type`

Is there an alternative to xdotool type "a string" It will be more useful if it is not an X11 app. Because X11 apps seem to be more vulnerable. Note: I will not use it in a terminal window. So ...
0
votes
1answer
53 views

Search a file for a string in multiple directories

Can someone please help me with a command to search a file for a string in multiple directories? I am searching for the VIP in httpd.conf in multiple httpd instances. I am using: find ./ -name ...
0
votes
0answers
43 views

Touch a file and give it an icon image via command line

Imagine this situation: for a given task, at some point of it, I should be able to create an empty file, which I can achieve by touch file.ext on the command line. However, if I touch a .jpg file, and ...
5
votes
3answers
498 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 ...
8
votes
10answers
6k views

linux diff tools: create list of modified files

How do I create a list of modified files programmatically using linux command line tools? I'm not interested in the difference in any particular file (delta, patch). I just want to have a list of new ...
1
vote
1answer
44 views

Only pipe on Success [duplicate]

Is there a way in the Linux command line, to only have a command pipe its output to another, when the command didn't fail? $ cmda | cmdb I would like it, so when cmda returns a status code other ...
0
votes
1answer
17 views

Makes it a difference whether I use a different -n flag value for xargs in combination with find command ?

Assume, someone searches for files that match some criteria using the find command and pipes the result into the rm command. find / -type f -name "*.jpg" | xargs rm First, I am not sure if the ...
1
vote
3answers
109 views

What is the reason for having numbers within the brackets of a function ? [duplicate]

I have seen on many occasions a name of a function (frankly speaking I just call it function because of it typical appearance, they are though sometimes named commands or system calls but I do not ...
4
votes
1answer
41 views

why does the output of xargs -n2 applied to the same number of arguments different whether piped or from keyboard?

when I execute xargs -n2, enter x x x x x and hit Enter, I get only 4 x back: $ xargs -n2 x x x x x x x x x But, when I pipe the x x x x x into the same command, I get the same amount of x back: ...
1
vote
1answer
71 views

Can not set the LC_TIME variable for the current process [duplicate]

On Linux Mint Rebecca, my current LC_TIME setting is LC_TIME="en_US.UTF-8" I would like to execute date and watch how the current date is displayed in a Chinese format with Chinese characters. ...
5
votes
2answers
10k views

executing if-statement from command prompt

In bash I can do the following: if [ -f /tmp/test.txt ]; then echo "true"; fi However, if I add sudo in front, it doesn't work anymore: sudo if [ -f /tmp/test.txt ]; then echo "true"; fi -bash: ...