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

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2
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1answer
14 views

Differences between “<command> < /dev/null &> /dev/null & disown” and “nohup <command> & disown”

This is my understanding about the usage of &, disown and nohup: <command>: runs the process within the Terminal's current bash instance, in the foreground (i.e. the process is listed as a ...
0
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3answers
33 views

Get Parent ID of last process executed in terminal

back to this How do I find the PID of the last open file in terminal? I want to know the PPID (parent id of the process) of the last executed process.
0
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1answer
30 views

How do I find the PID of the last open file in terminal?

How to know the PID of the last open file (process) using the command line?
6
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5answers
232 views

Exit terminal after running a bash script

I am trying to write a bash script to open certain files (mostly pdf files) using the gnome-open command. I also want the terminal to exit once it opens the pdf file. I have tried adding exit to the ...
0
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0answers
18 views

How to log bash history by editing bash source?

I'm using bash-4.3.30. I need to log all my commands history on a single file. I can do that by editing the bashrc or bash_profile but I'm not going to do that. I want to play with bash source ...
1
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0answers
15 views

How to check the password entered is a valid password for this user?

The scenario: In a bash script, I have to check if a password given by a user is a valid user password. I.e suppose I have a user A with password PA.. In the script I asked userA to enter his ...
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0answers
22 views

After changing Ubuntu 9 version to ubuntu 12.04.If i run my code i get core dumped segmentation fault

After upgrading from Ubuntu 9 to ubuntu 12.04, when I run my my shell (below) I get a: core dumped segmentation fault This code used to work before. My C-based applications still work. #! ...
0
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3answers
20 views

Problem when trying to run shell script : No such file or directory

I'm trying to run the following command on bash: ./home/abcdef/Desktop/jikesrvm/dist/prototype_x86_64-linux/rvm which is giving me a bash: ...
2
votes
1answer
114 views

How do I use the “^” and “$” symbols with regular expressions in a bash script?

How do I use the "^" and "$" symbols with regular expressions in a bash script? Please give me an example using both symbols.
0
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1answer
22 views

.bashrc edit messes up terminal command arrow-up history print

I wanted to give my terminal prompt in Ubuntu a more personal look, and wanted to change the text prior to the '$' when writing a command. From what I've found this is done by editing the .bashrc ...
0
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0answers
16 views

How to run a script when a directory is changed by another user?

I know has been a bit of discussion about topics similar to this. But here is what I am basically trying to do. I have a watch directory called and whenever a file is added to that directory, I want ...
1
vote
1answer
23 views

bash file for managing public private and history of website

I have a website and i have 3 versions I have the beta version with the most recent and usually not fully working changes. I have the public site that is on www. lastly, i have the history that I ...
0
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1answer
17 views

Unable to run apt-get with proxy even after setting the environment variables

I was trying to configure proxy in my lubuntu 14.04. Since I wanted to use the username and password for my proxy authentication, I opted ntlm and installed it. Now I can use my proxy link as ...
0
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1answer
12 views

having elevated priority and general @audio permssion in rc.local

I am trying to run jackd instance from /etc/rc.local (along with a few other applications) from a custom made init script. The system is ubuntustudio and I have setup everything to have elevated ...
5
votes
1answer
80 views

What do these commands from a shell script do?

I'm just starting to learn bash. I have the following script, and I would like to know what does the following commands do in order to start to understand a little bit this world. if [ ! -w "." ] ...
-1
votes
1answer
39 views

How to create logfile for a bash script?

I've written a bash script that runs multiple instances of a program and would like to write the entire output of the script to a logfile. I tried #!/bin/bash touch <.../somewhere/logfile.log> ...
4
votes
1answer
141 views

Writing a program that will demo the $PS2 variable

I've been customizing my terminal prompt, and found that it's possible to change the "secondary prompt". However, I have no way to test the changes I make to this one so I was wondering if a simple ...
0
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1answer
30 views

Running a command in screen daemon mode

I am trying to run a command in screen mode using the command screen -dmS screen_name sed -i 's/a/b/'g some-file.txt Nothing happens. When I put the same command in a script and run the command: ...
1
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2answers
22 views

Rsync --delete option doesn't delete files in target directory

I'm trying to use the --delete option in rsync to delete files in the target directory which isn't present in the original directory Here is the command I'm using: rsync -avz --ignore-existing ...
4
votes
4answers
296 views

Get previous commands in Terminal that match the currently typed command [duplicate]

In some terminals you can do something like this... Type some command nmap -sn 192.168.1.1/24 Then go on to do other things in the terminal for a while. Then later you can type nmap and then ...
1
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1answer
30 views

Different shells on SSH and local

So I've got an Ubuntu 14.04.2 computer that has OpenSSH Server installed on it. Whenever I use the computer locally, through the terminal, if I run: ~$ echo $SHELL /bin/bash However, if I SSH into ...
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3answers
39 views

What does this egrep command do?

I run this command egrep "\" string_demo | wc -l I got output below: akshay@akshay-K53SC:~/shell$ egrep "\" string_demo | wc -l > abc > pqr > xyz > ">" will continue until I press ...
0
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0answers
13 views

purpose of bamf-2.index [duplicate]

What is the purpose of /usr/share/applications/bamf-2.index ? I have noticed the applications it contains are installed in my computer. But I don't think it contains the complete list. Because the ...
0
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2answers
70 views

Enforce a shell script to execute a specific python version

Update. Changing the alias unfortunately does not work. I have changed the alias to alias python='/usr/bin/python2.7' however the shell script still runs the python script in 2.4.3. Muru - I am ...
1
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1answer
22 views

Customize Colors for Bash Terminal

I found this nice color library called Solarize which promises to liven up my hacking experience with a color terminal. I am not where to add the Solarize files to change. I found some ...
2
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3answers
152 views

Error when running script in bash

I wrote a script in bash to basically create aliases, but for any reason, it doesn't work in some cases. Here it's the code: #!/bin/bash #Script to create unique and permanent aliases _add_alias() { ...
1
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1answer
42 views

How to remove all lines in a file containing a string from another file

I want to remove all lines in a file containing a string from another file. So I don't want to remove the lines which are identical, there are none, but remove all lines if they share a string from ...
5
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3answers
214 views

Count down script is not working

I am trying to create a script that will count down to 0 from what ever number I give it. Below is my script and basically nothing happens, no error message, I merely get the standard command line ...
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0answers
28 views

Ubuntu shell script replace chars at position [closed]

I am making a hangman like game . where I've created the following pseudocode for : solution="solution" answer="........" guess(){ if($1 in solution) replace . at position with letter } So ...
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0answers
25 views

speech-dispatcher always stop working after terminal exit?

In a previous question I made this line: trap 'clear; ~/ascii3.sh; spd-say "Exit"; sleep 2' EXIT The content of ascii3.sh is: echo -e "\033[01;31m" echo " _ _ __ _ _ ____ __ __ _ ...
-1
votes
1answer
20 views

How to stop renaming a file which was already renamed using loop in shell script

I have a directory name dir1 containing another directories named 1,2,3,4,5. Now I want to rename directory 1 with 4, 2 => 5, 3 => 6, 4 => 5. but my problem is using mv command in shell script ...
1
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1answer
15 views

heredoc variables between underscores

Say I have something like this, tee filename <<EOF ... access_log /srv/users/serverpilot/log/$APP_NAME/$APP_NAME_nginx.access.log main; ... EOF where $APP_NAME is a variable. Bash ...
2
votes
1answer
29 views

sed to execute a command as replacement with substitution pattern as argument

I am trying to replace time in a log file by: cat mlog.log | sed -e "s/^[0-9\.]*/\$(date -d @&)/" Why it always first execute $(date -d $&) but not doing replacement at first and then ...
1
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1answer
39 views

USB mouse on Ubuntu stops working [duplicate]

Many times my mouse USB suddenly stops working, though the trackpad works just fine. I have to click it to make it work again. I have found the following solution: sudo bash for i in ...
0
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0answers
24 views

Running a bash script on “Switch User”?

I've had my first dabble with bash and got a working script going for each user on session start which checks if a NAS share is mounted and if it is unmounts it and mounts as the current user. This ...
1
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3answers
34 views

Force “bad” (not 0) return code of terminal command?

I have a framework written in python, and for testing purposes I basically want to do a subprocess (aka shell call) ... that should simply come back with a RC != 0. I tried to invoke some non-existing ...
2
votes
3answers
123 views

How to run a bash script after 20 sec on Login?

I want to run a bash script like: #!/bin/bash echo 'cpu limit bomi player at 40%' cpulimit -v -e bomi -l 40 Just 20 seconds after Login into my user. Can you please help me to do that? ...
2
votes
2answers
28 views

Timing limiter for execution of commands in Bash/Shell Script

I have a shell script which looks like this: echo firstOutput read -s command0 command1a command1b command1c echo secondOutput command2 command1a, command1b, command1c are individual commands but ...
0
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1answer
25 views

Create an alias for a directory while working in virtual environment

I've checked this. But right now I'm working in a virtual env. cam@cam:~$ cd Desktop/django-user3 cam@cam:~/Desktop/django-user3$ source newenv/bin/activate (newenv)cam@cam:~/Desktop/django-user3$ ...
12
votes
1answer
608 views

opposite of eject command?

I have a ton of CDs to image, and I just got curious. I can eject with the eject command. What command inserts the disk tray back into the CD drive? yes it is the type that can pull the tray back in. ...
4
votes
3answers
264 views

improve bash script

I have a quad core desktop, and i wanted to know the average temprature according to sensors. so i wrote this bash 1 liner. echo `sensors -A | awk {'print $3'} | sed 's/+\|(crit\|0:\|°C//g'` | awk ...
-2
votes
4answers
54 views

Why am I getting a syntax error in this script?

When running the script below, I get an error: The script is: clear echo "Enter a num" read num if [ "$num" -ge 0]; then f=1 i=1 while [ $i -le "$num" ]; do f=`expr $f \* $i` ...
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votes
0answers
20 views

Conditional statements go wrong when set Shortcut

( C=1 if [ $C == 1 ] then echo "True" else echo "False" fi ) > ./log.txt When i run it in terminal, it output True (expected), but when I set a shortcut keyboard to run ...
6
votes
3answers
318 views

How do I search shell command history with a text editor?

I know that Ctrl+R let's you search command history, but it's a little primitive. Is there a way to export all my command history (not just the current terminal session, but the full history) to a ...
2
votes
1answer
106 views

I see one backslash, but there are actually two backslashes!

Does anyone can help me to understand that weird issue? I was trying to rename a very long list of folders. I went to the parent directory and listed all the folders to rename in a text file: find ...
1
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1answer
34 views

Why is this odd file extension appearing when I scp a file?

I'm creating a large number of gifs and copying them to a separate computer with a webserver folder mounted via sshfs. For some reason the files will randomly copy with *.gif.001 file extensions. My ...
3
votes
1answer
43 views

Is there a bash/terminal command that will clear content prior to the last command?

Use case: I'm working in bash/terminal and have been typing several commands and I've just run something and it's spewed some output. I'm trying to find where that output started and have to visually ...
0
votes
1answer
25 views

how to stop using export command

every time I run gdb I have to type export SHELL=/bin/bash or gdb would return exit with code 127 my question how to make this command run every time automatically without need to re type it because ...
3
votes
1answer
44 views

Create zip files in /var/www/html using crontabs

As the title explains, I'd need to take a file and put it into a zip archive once a day; also, the zip file has to be moved in /var/www/html, where a .php scripts allow users to download it. Assuming ...
2
votes
2answers
118 views

Bash Script does not work?

I made a script to check if sdb or sdc drives are present. but even when I have both or one of them present the script is terminating. what is wrong with my script? HDD1="sdb" HDD2="sdc" echo ...