Script is series of instructions written in plain text file. The script interpreter (i.e. shell, Python, Ruby, etc.) can read this file and act on the instructions as if they were typed at the command prompt. The interpreter also provides a variety of useful programming features to make your scripts ...

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114
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1answer
77k views

Differences between /bin, /sbin, /usr/bin, /usr/sbin, /usr/local/bin, /usr/local/sbin [duplicate]

I'm running an Ubuntu Server 13.04, but I see the same on a 12.04: I have six directories with command files. These are: /bin /sbin /usr/bin /usr/sbin /usr/local/bin /usr/local/sbin What are the ...
80
votes
5answers
98k views

How can I get a list of all repositories and PPAs from the command line?

I know how to list all packages installed on my system. But how could I get a list of all repositories and PPA's? I know I can look into /etc/apt/sources.list and /etc/apt/sources.list.d, but I'm ...
74
votes
3answers
162k views

What is difference between #!/bin/sh and #!/bin/bash?

if I write, #!/bin/bash echo "foo" or #!/bin/sh echo "foo" both yields same. I have seen some scripts starting with #!/bin/sh or #!/bin/bash. Is there any difference between them?
71
votes
2answers
25k views

What is the difference between “source” and “.” in bash?

As the question says, what is the difference between executing a script with source command and with . , i.e.: source /some/script and . /some/script
69
votes
3answers
90k views

ssh: automatically accept keys

I've written this small utility script: for h in $SERVER_LIST; do ssh $h "uptime"; done When a new server is added to $SERVER_LIST, the script is stopped with: The authenticity of host ...
56
votes
1answer
8k views

Can I make the webcam take a picture when an incorrect password is entered?

I am using a laptop . I was thinking to have a support in my Ubuntu machine. When an incorrect password is entered, a picture is taken later revealing who has been trying to gain access. I have ...
54
votes
8answers
67k views

Repeat a command every x interval of time in terminal?

How can I repeat a command every interval of time , so that it will allow me to run commands for checking or monitoring directories ? There is no need for a script, i need just a simple command ...
54
votes
5answers
14k views

How do I create a deb package for a single python script?

I have a single python script that I want to distribute as a deb package. It is a indicator which shows local date in Unity panel. I did follow create a .deb Package from scripts or binaries but I ...
52
votes
2answers
107k views

How to add a shell script to launcher as shortcut [duplicate]

Possible Duplicate: How can I edit/create new launcher items in Unity by hand? How can I create launchers on my desktop? I want to add some shell scripts in my launcher as shortcuts.. ...
50
votes
14answers
153k views

How can I create a select menu in a shell script?

I'm creating a simple bash script and I want to create a select menu in it, like this: ./script echo "Choose your option:" 1) Option 1 2) Option 2 3) Option 3 4) Quit And according to ...
50
votes
3answers
6k views

Is #!/bin/sh read by the interpreter?

In bash or sh, I guess anything which starts with # is a comment. But in bash scripts we write: #!/bin/bash And in Python scripts, there is: #!/bin/python Does this mean that # by itself is a ...
48
votes
6answers
18k views

What is the difference between ./ and sh to run a script?

I have written a simple script. When I runsh <myscriptname.sh>, i got the correct output, but when I run ./<myscriptname.sh>, I got an error. What is difference between when I do sh and ...
48
votes
1answer
123k views

Command to append line to a text file without opening an editor

Assuming i have a line that i want to add to a file without opening an editor. How could i append this line alias list='ls -cl --group-directories-first' to this file config.fish
45
votes
4answers
5k views

When to use () vs. {} in bash?

I'm studying shell scripting with bash and I need to know the difference between (...) and {...}. How does one select between the two when writing a script?
44
votes
3answers
154k views

'chmod u+x' versus 'chmod +x'

What is the difference between chmod u+x and just chmod +x? I have seen a ton of tutorials that say to use u+x to make scripts executable. However, the u is not mentioned in the chmod help or ...
43
votes
4answers
113k views

How can I make a script that opens terminal windows and executes commands in them?

I have three scripts I need to run when I start up my Ubuntu machine, they start services I use in my development environment. To do that, I manually open three terminals and type in the commands. ...
43
votes
7answers
70k views

How to execute a script just by double clicking like .EXE files in Windows?

How can I make a bash script executable by double clicking just like .exe files in Windows? I tried creating a launcher and assigning the script to it, but there are two consequences: the terminal ...
40
votes
0answers
10k views

How can I determine whether a shellscript runs as root or not? [duplicate]

Possible Duplicate: How can a script check if it’s being run as root? This is something I've been curious about. I make a lot of small bash scripts (.sh files) to do tasks that I routinely ...
39
votes
6answers
108k views

Bash remove first and last characters from a string

I have a string like that: |abcdefg| And i want to get a new string called in someway (like string2) with the original string without the two | at the start and at the end of it so that i will ...
39
votes
3answers
5k views

Should I save my scripts with the .sh extension?

I have some functional scripts and I want to copy to /usr/bin I want to use them as normal terminal commands. Is it a good practice to use them with the .sh extension or can I save them without ...
38
votes
6answers
43k views

Beep in shell script not working?

I'd like to use a beep sound in a shell script. Unfortunately none of the methods I found via Google work for me. I tried echo -e '\a' echo -ne '\007' and the command beep after I installed it ...
37
votes
2answers
8k views

bashrc or bash_profile?

I know the difference between the two bash login scripts: .bashrc is run only by "non-login" shells. .bash_profile (or .bash_login or .profile) is executed by "login" shells. Does anyone have some ...
36
votes
4answers
130k views

I've downloaded a .sh file - how do I install this?

I'm new to Ubuntu and know installing programs only from window. It is very easy there: Just double-click the setup.exe and the things start. But how do I install a program on Ubuntu? I want to ...
36
votes
4answers
8k views

How to make Skype use notify-osd?

How do I make Skype use the default Ubuntu notify-osd to display notifications (incoming messages, users connecting, etc.) instead of the Skype's own "ugly" message box?
34
votes
7answers
4k views

Why does Python in Linux require the line #!/usr/bin/python?

Pretty simple question: In Linux, why does Python require the line #!/usr/bin/python at the start of a python file, since Windows doesn't? What does it do? 'cause the description "Links to ...
33
votes
6answers
60k views

How to run an alias in a shell script?

I have an executable file mpiexec, whose full path is ~/petsc-3.2-p6/petsc-arch/bin/mpiexec. Since I want to execute this command in different directories (without having to retype the entire path), ...
30
votes
8answers
22k views

How can a script check if it's being run as root?

I'm writing a simple bash script, but I need it to check whether it's being run as root or not. I know there's probably a very simple way to do that, but I have no idea how. Just to be clear: What's ...
30
votes
1answer
2k views

How can I make cowsay say something every time I close the terminal?

I want cowsay to print something like "have a nice day" when I close the terminal. I know I have to have some kind of script, but I'm not even sure how to write a script or how to use it once it's ...
29
votes
8answers
2k views

How to keep “dot files” under version control?

Etckeeper is a great tool for keeping track of changes to your configuration files in /etc A few key things about it really stand out. It can be used with a wide variety of VCSs: git, mercurial, ...
28
votes
1answer
16k views

how to execute a command after resume from suspend?

I've got a script that is executed in order to have suspending/resuming working in my laptop. Then I have another series of xinput,xkbset and xmodmap commands that are executed when I initiate a ...
26
votes
3answers
4k views

Where should I put my script so that I can run it by a direct command?

Where can (should) I put my (bash) script so that it can be used (forever) by terminal or by a direct command: Alt+F2? I know there is /usr/bin and /sbin & /bindirectories but when should I use ...
25
votes
6answers
38k views

Upstart script doesn't start

Ubuntu 10.04 I have created this upstart script (/etc/init/pure-ftpd.conf): # pure-ftpd - FTP server description "Pure-FTPd server" start on filesystem stop on runlevel S respawn respawn limit ...
25
votes
3answers
149k views

How can I make “rc.local” run on startup?

I have a script that I would like to run when my system starts. I have put it on "rc.local", but it doesn't work. How can I enable it to run on startup?
25
votes
3answers
11k views

Record a programs output with PulseAudio

I would like to record an output of a program with PulseAudio using command line/bash script. It is important not to record every output of the sound card, but only the one of one specific program. I ...
24
votes
2answers
72k views

How to read complete line in 'for' loop with spaces

I am trying to run a for loop for file and I want to display whole line. But instead its displaying last word only. I want the complete line. for j in `cat ./file_wget_med` do echo $j done result ...
24
votes
5answers
21k views

Script to display all terminal colors

Throughout the internet I have seen many people with scripts that prints out a bunch of stuff in all the colors defined in ~/.Xdefaults. However when I try to use these, I always get error: Bad ...
24
votes
6answers
70k views

Not able to execute a .sh file: /bin/bash^M: bad interpreter

I wanted to execute a shell script: -rwxr-x--x 1 root root 17234 Jun 6 18:31 create_mgw_3shelf_6xIPNI1P.sh I tried to do a standard procedure, but I am got this error: ...
23
votes
7answers
39k views

Command to convert an upper-case string to lower-case?

What is the Bash command I can use to convert an upper-case string to lower-case and vice-versa? Thank you.
23
votes
3answers
5k views

Can I modify a bash script (.sh) file while it is running?

Suppose I have a script script.sh, which takes some time to execute. I execute it, ./script.sh. While it is running in a terminal window, I modify the file script.sh. Will this have any effect on the ...
22
votes
3answers
24k views

Why doesn't “cd” work in a shell script?

What is wrong with this easy script? I just want to write an script which change my directory: A. I put below commands on the file witch its name is pathABC on the /home/alex directory, #!/bin/sh cd ...
22
votes
6answers
91k views

How to determine if a string is a substring of another in bash?

I want to see if a string is inside a portion of another string. e.g.: 'ab' in 'abc' -> true 'ab' in 'bcd' -> false How can I do this in a conditional of a bash script?
21
votes
5answers
62k views

How to run a script during boot as root

I had a script that automatically enables my wifi without using networkmanager, but I don't know how to run the script as root while the system is booting. How do I make the script run automatically ...
21
votes
2answers
50k views

How Do I fetch only the numbers in grep?

I have file like this : other lines . . . blah blah blah (:34) I wish to find the occurrence of numbers in the above file. I came up with : grep [0-9] filename But that is printing the ...
20
votes
4answers
71k views

How do I run 'sudo' command inside a script?

To do a patch manually I must type this command sudo ./playback_delete_data_patch.sh 09_delete_old_data_p.sql There is a space just before the 09: sudo ./playback_delete_data_patch.sh [space] ...
20
votes
2answers
3k views

Know whether the shell script contains syntax error without running the script

I have a long shell script containing a lot of conditions and I want to know whether there is any syntax error in the script without running it. Since shell script is interpreted I think it is not ...
20
votes
2answers
69k views

How do I run a script after OpenVPN has connected successfully?

How can I associate a script to OpenVPN so that it runs when the VPN is connected successfully?
19
votes
10answers
2k views

How to write a shell script to assign letter grades to numeric ranges?

I want to make a script that would prompt you for a number between 0-100 and then give you the grade based on the number. I'd like it in bash. PS3='Please enter your choice: ' (Something here) do ...
19
votes
7answers
100k views

How to run scripts every 5 seconds using cron?

I have a script that needs to be run every five seconds. I know that cron can do tasks by the minute, but is there a way to run something every second?
19
votes
3answers
37k views

At what time does cron execute daily scripts?

If I place a shell script in /etc/cron.daily/, at what time of the day will it be executed?
19
votes
4answers
943 views

How to enter password only once in a bash script needing sudo

Data I want operator users on this machine to mount their own cifs shares The sudoers file already contains the /bin/mount -t cifs //*/* /media/* -o username=* command for all operators I want the ...