Bash is the shell used in Ubuntu's command-line interface.

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21
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How to run scripts without typing the full path?

I'd like to know if there is a way to run program/shell script without typing full path: /opt/idea/bin/idea.sh
73
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7answers
150k views

Running programs in the background from terminal

How do I run a program in the background of a shell, with the ability to close the shell while leaving the program running? Lets say my UI is having problems or for some reason, I need to boot up a ...
159
votes
8answers
285k views

How do I create a permanent Bash alias?

I would like to create an alias to rm command in order to have a confirmation message after executing this command. So I am creating an alias like this alias rm='rm -i'. But as far as I know this is a ...
79
votes
11answers
538k views

How do I run .sh files?

Whenever I open a .sh file, it opens it in gedit instead of the terminal. I can't find any option similar to Right Click → Open With → Other Application... → Terminal. How do I open this file in the ...
46
votes
10answers
37k views

How do I restrict my kids' computing time?

Access to our computer (not only to the internet) needs to be restricted for the accounts of my kids (7, 8) until they are old enough to manage this by themselves. Until then we need to be able to ...
62
votes
4answers
63k views

How can I shorten my command line (bash) prompt?

Currently it is: michael@Castle2012-Ubuntu-laptop01:~/Dropnot/webs/rails_v3/linker/spec/controllers$ Outside of renaming my machine and directory structure... How could I make it be something ...
132
votes
5answers
97k views

What is the CVE-2014-6271 bash vulnerability (Shellshock) and how do I fix it?

Recently, there have been news going around regarding "CVE-2014-6271" (See USN-2362-1), which is a vulnerability in Bash. How do I know if I am affected by this, how can I fix it, and why should I ...
77
votes
3answers
225k views

How do I use variables in a sed command?

I tried the following code and it doesn't do what I want: var1=QQ sed -i 's/$var1/ZZ/g' $file However, this code replaces QQ with ZZ: sed -i 's/QQ/ZZ/g' $file How do I use variables in sed?
28
votes
6answers
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Differences between doublequotes “ ”, singlequotes ' ' and backticks ´ ´ on commandline?

I often see tutorials on the web or posts on this site which make heavy use of the following characters at the command line. Often it seems that they are used for pretty similar purposes. What are the ...
101
votes
1answer
136k views

'sudo su -' vs 'sudo -i' vs 'sudo /bin/bash' - when does it matter which is used, or does it matter at all?

When I'm doing something that requires root be typed in dozens of times in a row, I prefer to switch my session to a root session. In the various tutorials and instructions I have used on the Internet,...
53
votes
3answers
92k views

BASH script to set environment variables not working

I've written the following script to set some environment variables when needed. #!/bin/sh export BASE=/home/develop/trees echo $BASE export PATH=$PATH:$BASE echo $PATH Below the command and the ...
96
votes
4answers
139k views

Why ~/.bash_profile is not getting sourced when opening a terminal?

Problem I have an Ubuntu 11.04 Virtual Machine and I wanted to set up my Java development environment. I did as follows sudo apt-get install openjdk-6-jdk Added the following entries to ~/....
53
votes
6answers
539k views

How to copy files via terminal?

I have read about copying files with terminal but these examples will help me a lot. So here is what I want to do: Examples: I have a file in /home/levan/kdenlive untitelds.mpg and I want to copy ...
52
votes
3answers
7k 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 ...
29
votes
1answer
28k views

Scripts in /etc/profile.d Being Ignored?

I'm new to Ubuntu. I'm running 13.10 Desktop. I wanted to set some system wide aliases and a custom prompt for bash. I found this article: https://help.ubuntu.com/community/EnvironmentVariables ...
2
votes
1answer
264 views

Pass variables to script which called script [duplicate]

I have a bash script which must call another bash script which varies per-user in order to get some configuration information, like so: somescript: #!/bin/bash ${HOME}/.ssconfig echo "Hello, ${...
70
votes
4answers
35k views

Bash history search, partial + up-arrow

I have searched, but not found anything on this. I am looking for a functionality in bash, using a terminal. Way back when, I had a user on a debian system, and a friend set me up with a convenient ...
19
votes
8answers
43k views

How do I rebuild a corrupt dpkg status file?

Whenever I type sudo apt-get remove and then press the Tab key for auto-completion I get the following message: grep-status: /var/lib/dpkg/status:15945: expected a colon . I don't see anything ...
1
vote
1answer
3k views

How can I capture text from a specific terminal and redirect it to a log file while simultaneously working? [duplicate]

I viewed this question to redirect text to file while displaying the output. My question is how can I redirect it while working AND without constant | tee command. My plan is to use this question to ...
71
votes
10answers
61k views

Why do I need to type `./` before executing a program in the current directory?

While executing a C program, a.out, using the Ubuntu terminal, why do I always need to type ./ before a.out, instead of just writing a.out? Is there solution for this?
39
votes
10answers
9k views

Delete all files except files with the extension pdf in a directory

I have a directory that contains the following: x.pdf y.zip z.mp3 a.pdf I want to delete all files apart from x.pdf and a.pdf. How do I do this from the terminal? There are no subdirectories so no ...
14
votes
1answer
4k views

Sequence of scripts sourced upon login

I would like to concentrate all my login config in my ~/.bash_profile. There was a ~/.bashrc there by default but I replaced it with a ~/.bash_profile. However, when I log in, something before my ~/....
4
votes
1answer
7k views

Run simple bash script to start applications at login

I want to run a simple bash script automatically when I log in. For example #!/bin/bash echo "start spotify" gnome-terminal -e spotify --title spotify When I run this command, one gnome-terminal ...
33
votes
5answers
65k views

How do I modify my PATH so that the changes are available in every Terminal session

I want to add a directory to search my search path. I know I have to modify the $PATH environment variable. However, I want the change to be permanent, so that it is always in effect, for every ...
23
votes
5answers
23k views

trim the terminal command prompt working directory

When using the terminal in a deep folder structure sometimes the prompt can take up most of the line. Is there any way in which I can trim the working directory? I know I can do PS1="\W >" to ...
12
votes
3answers
14k views

Is there an easy way to log all activity that a shell script does?

Is there an easy way to log all activity that occurs from a shell script to a file? I have a script. It outputs things like echo "instructions", as well as other program output. I know the commands: ...
9
votes
2answers
6k views

Is it possible to color the prompt in Bash?

Is it possible to color the prompt ("user@host:~/dir/$") in Bash? Some commands generate a lot of output and it's sometimes hard to find where it started. Coloring would help a lot.
7
votes
3answers
2k views

How can I make a list with most used commands in terminal?

How can I make a list with most used commands in terminal? I know that this question may be unuseful for any future proposals for some of us, but even like this, the list can be useful when we don't ...
141
votes
5answers
113k views

Which one is better: using ; or && to execute multiple commands in one line?

In tutorials and how-to's I often see commands combined. For instance, sudo apt-get update && sudo apt-get install pyrenamer There seem to be four possible connectors: &, &&, || ...
124
votes
8answers
316k views

How to clear bash history completely?

I want to clear all before command from history of my server. I use history -c it seems all things are cleared but when I ssh to the server,all commands are still there. How can I clear them ...
146
votes
6answers
212k views

How to list all variables names and their current values?

Including not only $HOME, $PWD etc but any other you have defined.
51
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2answers
32k views

What are login and non-login shells?

It is said that settings for non login shell to go into .bashrc file and login shell settings to go into .profile file. What is really meant by login and non-login shells? Please explain without ...
60
votes
14answers
184k 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 ...
34
votes
3answers
10k views

What does “${debian_chroot:+($debian_chroot)}” do in my terminal prompt?

In my terminal prompt definition in my .bashrc file, among other things, I have this snippet of code: ${debian_chroot:+($debian_chroot)} What does this do, and do I need it?
6
votes
2answers
4k views

“No such file” when running a 32-bit program on a 64-bit system

I downloaded a Chromium snapshot and unzipped it, like this: michael@ubuntu:/opt/chrome-linux$ ls chrome libffmpegsumo.so nacl_irt_x86_32.nexe chrome.1 ...
0
votes
2answers
2k views

UEFI machine doesn't boot Ubuntu through NVRAM bootcatalog. How to fix?

Edit: It currently looks like this Q&A wasn't useful to anybody. I will remove it some time in the future. An answer posted here should: Avoid to require the user to download and ...
81
votes
5answers
55k views

Hide current working directory in terminal

As a default, the terminal prompt shows something like: user@system:/folder1/folder2/folder3/folder4$ the deeper you go into the filesystem, the less space is left for typing in commands. Can I ...
58
votes
3answers
98k views

How to see time stamps in bash history?

Is there any way I can see at what time the commands were executed from the bash history? We can see the order but is there any way I can get the time also? Bottom-Line: Execution time in the Bash ...
36
votes
5answers
67k views

How to change extension of multiple files from command line?

I have many files with .abc extension and want to change them to .edefg How to do this from command line ? EDIT: I have a root folder with many sub-folders, so the solution should work -r recursively....
31
votes
4answers
75k views

How do I clean or disable the memory cache?

After the system starts, in a few minutes my memory cache fills up and it starts using the swap. Here's a screenshot of /proc/meminfo. However, if I can disable this process / clean the cache once ...
44
votes
5answers
21k views

How to avoid duplicate entries in .bash_history

The same command is listed in my history again and again. How can I avoid this? I know it's possible via HISTCONTROL but I haven't found the right way.
25
votes
4answers
4k views

How does using the tilde work as a shortcut to my home directory?

I was confused, trying to copy some files from one PC to another. I have it figured out, but the syntax is still confusing to me. This works: scp ~/Desktop/Volenteer.png jay@server.ip:~j0h/b which ...
18
votes
6answers
39k views

How do I insert a line at the top of a text file using the command line?

I want to insert text at the top of an already existing file. How can I achieve this. I tried echo and tee but was not successful. I was trying to insert repo line at the top of sources.list file ...
12
votes
2answers
2k views

What does the l command do?

There is a command l available on my machine which appears to do nothing. which l also produces no output. Is this a real command, and does it actually do anything?
96
votes
3answers
197k 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?
82
votes
2answers
31k 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
31
votes
8answers
28k 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 ...
24
votes
5answers
45k views

How do I use wget/curl to download from a site I am logged into?

Some parts of wikipedia appear differently when you're logged in. I would like to wget user pages so they would appear as if I was logged in. Is there a way I can wget user pages like this http://...
34
votes
9answers
108k views

How to remove all files and subdirectories in a directory WITHOUT deleting the directory in bash?

Is there a command to remove all files and subdirectories in a directory WITHOUT deleting the directory? For example if I have directory "dontDeleteMe" with subdirectories "1", "2", "3" and each ...
27
votes
6answers
15k views

How can I create an alias for cd and ls?

I frequently run the ls command after running the cd command. How can I create an alias (like cs) for this operation?