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

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15
votes
2answers
1k views

Create a test file with lots of zero bytes

I know how to create an empty file: touch /var/tmp/nullbytes but how can I create a 1MB file that only contains nullbytes on the commandline with bash?
2
votes
2answers
22 views

How to extract info from console output, between two specific lines?

How can I get the part of a console output, between two specific lines? A dummy example: Command: git for-each-ref --sort='*authordate' --format='%(tag)' refs/tags | grep -v '^$' Output: 0.1.0 ...
1
vote
1answer
68 views

Command-line parameters in bash script not recognised

I use Debian (Raspbian) Wheezy. If this command line works fine: smsd -c sms/out -i 60 -0 -f sms/smsd.log and this alias also works fine: bsmsd='smsd -c sms/out -i 60 -0 -f sms/smsd.log' then ...
27
votes
5answers
5k views

How to echo a bang!

I tried to create a script by echo'ing the contents into a file, instead of opening it with a editor echo -e "#!/bin/bash \n /usr/bin/command args" > .scripts/command The output: bash: ...
1
vote
2answers
3k views

checking running process

I am new babe to Linux. So please skip to read if you are not patient with begineer. Let's say I am asked to check and shut down the processes that I am not familiar with. So when I ls under bin ...
2
votes
1answer
43 views

Login to Skype from terminal or any other way

Please let me know if anybody knows how to login to Skype on Linux Mint from terminal or any other way? I have tried a lot but nothing found. Desktop # ./skype.desktop ./skype.desktop: line 1: ...
1
vote
1answer
34 views

Listing audio files with bit rate in the command line

Is there a way to list the contents of a folder via the command line in such a way that the audio files in mp3 format have the bit rate info? I tried ls -l but it doesn't work.
7
votes
2answers
236 views

Is there a shortcut for repeat the second proximate command in bash?

We all know that !! can repeat the last command you do in bash. But sometimes we need to do some operation like $ python test.py $ vim test.py $ python test.py # here is where I need to repeat the ...
0
votes
0answers
23 views

characters stick at the CLI [duplicate]

When I press arrow up to search through the command history, some characters always remain at the beginning of the command line. Does anyone know what's going on ? How can I fix it? for example, I ...
8
votes
4answers
3k views

command to layout tab separated list nicely

Sometimes, I'm getting as an input tab separated list, which is not quite aligned, for instance var1 var2 var3 var_with_long_name_which_ruins_alignment var2 var3 Is there an easy way to render ...
13
votes
2answers
983 views

Coloring different sources for tail

I'm watching different logs by tail -q -f /var/log/syslog -f /var/log/fail2ban.log -f /var/log/nginx/error.log How can I have the output of each log colored differently?
4
votes
3answers
45 views

Is it possible to view the list of file names of a zip file which is inside another zip file?

I know I can use unzip -l file.zip to view the file list of a zip file. But a got a zip file inside another zip file. I tried unzip -l file.zip/sub_file.zip, but failed. Is it possible to view the ...
3
votes
4answers
417 views

Shell: How do I get the last argument the previous command when it was detached?

Within the shell, typing ALT+. or using !$ recalls the last passed argument of the previous command. I use this all the time, but how do you do that when you detached the previous command? $ ...
117
votes
5answers
21k views

I deleted /bin/rm. How do I recover it?

Just for fun, I thought I would use this command on my Raspberry PI running Raspbian: sudo rm -f /bin/rm I thought I could just reinstall coreutils: I was wrong! apt-get install --reinstall ...
0
votes
1answer
32 views

Less command change color of “~” and “(END)”?

How do I change the color of the "~" characters that go along the edge of a Less command output. And how to change the color "(END)" at the bottom?
15
votes
1answer
4k views

What are the differences between most, more and less?

I'm now using Arch Linux, and find a command most works like more and less. To understand the differences between them is a confusing problem. This Question has mentioned the differences between less ...
2
votes
2answers
68 views

How parse a log file for a string, and when found search backwards for another string

I use the following command to parse a log file for a particular string. Then I search backwards in the log to find the data I really want. The problem as in the example below, I am only going back ...
1
vote
5answers
1k views

Checking if a file exists in several directories

I've been working on this far too long and need some help. I need a script that will look at files in a directory and see if it exists in one of several directories. I need something like this: for ...
96
votes
26answers
16k views

Tracking down where disk space has gone on Linux?

When administering Linux systems I often find myself struggling to track down the culprit after a partition goes full. I normally use du / | sort -nr but on a large filesystem this takes a long time ...
1
vote
1answer
695 views

How to access u boot environment from linux?

How can I access and change the u-Boot env variables in linux. Using the u-boot/tools/env directory in u boot directory: u-boot$ make env Which created the executable file fw_printenv. I copied ...
13
votes
1answer
5k views

How do I find the window dimensions and position accurately including decorations?

I've been trying to figure out the size of a window for use in a small script. My current technique is using wmctrl -lG to find out the dimensions. However, the problem is this: The x and y figures ...
2
votes
3answers
36 views

Convert a number of seconds elapsed to date from arbitrary start date

I want to convert a particular amount of seconds to a date. In my case the it's the number of seconds elapsed since 1st of January 0001. If it were for seconds elapsed from epoch it would be easy: $ ...
4
votes
1answer
234 views

How to rollback network configuration changes done over SSH in case of failure?

I'm about to change iptables configuration and interface speed and duplex settings over SSH. What are the possibilities to rollback the changes in case of host becomes unreachable? I guess simple: ip ...
3
votes
2answers
397 views

Jingle CLI client / Jitsi replacement / VOIP

I am looking for a Jingle client for the command line. Currently, I use Jitsi, but my dreams of not needing the GUI for more than just web-browsing are not realized due to my reliance on this ...
3
votes
3answers
81 views

How can I delete text before a delimiter in Linux

I need to delete text from a line before delimiter. For example: (123434): hello::{apple,orange,mango}. I need to delete text before first :. i.e. (123434). Is there any command in linux to ...
0
votes
3answers
96 views

Mounting /dev/dvd /media on VirtualBox

I have installed Scientific Linux on VirtualBox and I am trying to follow some exercises on a book I picked up. The first thing I need to do is: mount /dev/dvd /media But when I do that, I get ...
18
votes
10answers
6k views

Is there a robust command line tool for processing csv files?

I work with CSV files and sometimes need to quickly check the contents of a row or column from the command line. In many cases cut, head, tail, and friends will do the job; however, cut cannot easily ...
4
votes
2answers
155 views

Change user info on the command line

I have made a user in Mint 16 but want to change its first and last name without deleting it and starting from scratch. I know how to do it with a GUI but I want to know the terminal command ...
4
votes
3answers
252 views

How to pass each line of a text file as an argument to a command?

I'm looking to write a script that takes a .txt filename as an argument, reads the file line by line, and passes each line to a command. For example, it runs command --option "LINE 1", then command ...
0
votes
1answer
38 views

How to start a cron task?

It sounds really simple, but many times I was stuck at the beginning of learning a new command. The tutorial writer think it's natural to start, but it's not. This is the tutorial I've been reading: ...
5
votes
3answers
673 views

Recursively add a file to all sub-directories

How do I recursively add(or touch) a file into the current directory, as well as all sub-directories? For example, I would like to turn this directory tree: . ├── 1 │   ├── A │   └── B ├── 2 │   └── ...
17
votes
7answers
2k views

how to glob every hidden file except current and parent directory

I want to glob every hidden file and directory, but not the current (.) and parent directory (..). I am using bash. Observe current behaviour: $ ls -a . .. ...a ...aa ..a ..aa .a .aa .aaa ...
3
votes
1answer
158 views

How do I re-stream a filtered video stream using VLC?

I have an input RTSP stream that I want to apply the "cartoon" gradient filter to before streaming on http. I've managed to stream and apply the filter to the local playback, but the http stream does ...
1
vote
3answers
85 views

How to disable a shell keyword?

Using enable builtin command we can disable a shell builtin command, for example echo, as follow: enable -n echo But how can we disable a shell keyword like time? If we try: enable -n time we ...
70
votes
6answers
39k views

How can I close a terminal without killing the command running in it?

Sometimes I want to start a process and forget about it. If I start it from the command line, like this: redshift I can't close the terminal, or it will kill the process. Can I run a command in ...
6
votes
2answers
175 views

How many commands can be queued up with control operators?

I have been reading up on control operators, and I was wondering if there was a limit to how many commands you could line up with control operators, such as ||, && and ;. In addition, is ...
2
votes
7answers
83 views

Printing specific section of a line when a trigger value is present

I'm parsing data in the following format: prop1=value1:prop2=value2:prop3=value3+prop1=value4:prop2=value5 parts of the string are delimited by + properties can appear in any order the desired ...
1
vote
2answers
85 views

Pass a command to ROOT from a shell script and having it stay open

I am writing a bash script to perform some analysis using the program ROOT. I want to run some initial command to load the result of the analysis, then continue using ROOT interactively. The analysis ...
3
votes
0answers
154 views

Read out pulseaudio volume from commandline? (I want: “pactl GET-sink-volume”)

I want to read out the volume level I can set with pactl set-sink-volume $SINK $VOLUME Is there an easy way to do that? As easy as the hypothetical pactl get-sink-volume $SINK ? (What I'm ...
3
votes
4answers
257 views

Make many subdirectories at once

Suppose I have a directory /, and it contains many directories /mydir, /hisdir, /herdir, and each of those need to have a similar structure. For each directory in /, there needs to be a directory doc ...
0
votes
1answer
406 views

Proper escaping of double quotations for curl post data?

I'm trying to test out a server, by sending it JSON data and reading the response. I need to POST data like {"item":"value with spaces"} but when I use curl I find that it sends the backslashes as ...
106
votes
15answers
41k views

How to do integer & float calculations, in bash or other languages/frameworks?

Using echo "20+5" literally produces the text "20+5" What command can I use to get the numeric sum, e.g. 25 in this case. Also, what's the easiest way to do it just using bash for floating point, ...
4
votes
5answers
4k views

How can I logout from a graphical environment from the command line?

Part of the beauty of trying out alpha releases of operating systems is that things will break, including things we take for granted. Today it's the turn of the logout button. So, how do you log out ...
3
votes
1answer
3k views

Better way to copy multiple directories to new directory

Is there a better way on the command line to essentially accomplish the following but with a single command cp -r css/ ar/ cp -r images/ ar/ cp -r js/ ar/ cp -r backups/ ar/ I've just been ...
4
votes
5answers
805 views

Use xdg-open to open a url with a new process

I'm starting to experiment with Crunchbang (which is based on Debian, and uses terminator) as a web development environment, and one of the things I am struggling with is the behaviour of xdg-open. I ...
2
votes
2answers
30 views

Select a range of files after sorting them

One thing I notice slower for me if I switch from using a GUI file manager to CLI is: In a GUI file manager, I can quickly select a subset of files under a dir by, first sorting them according to ...
6
votes
6answers
535 views

How can I reproduce commands run on one machine on another machine?

I would like to install some software on a linux-machine that I have run in VirtualBox. Then I would like to do the same thing on a linux-VPS. I think that I can save all commands that I run using ...
12
votes
6answers
6k views

How can I display the contents of a text file on the command line?

I would like to display the contents of a text file on the command line. The file only contains 5-6 characters. Is there an easy way to do this?
1
vote
3answers
43 views

Command to 're-apply' previous command?

Is there an easy way to re-apply a previous command to a new command line entry? Say I typed in chmod u+r,g+x file.txt but forgot the sudo. Could I simply type sudo <some easy symbol>'? ...
9
votes
4answers
3k views

Remove all `at` jobs

I know that to remove a scheduled at job I have to use atrm "numjob1 numjob2", but is there an easy way to do that for all the jobs?