Bash is a free shell for Unix-like operating systems from the GNU Project.

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How to verify that hard drive is filled with zeroes in Linux?

I have hard drive filled with zeroes. How to check if all bits on hard drive are zeros using bash?
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5answers
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How to color grep output

When I type memcached -vv 2>&1 | grep --color=always "SET\|GET" I get nice memcached stats GET AR-City-1 GET rest-part-241 SET rest-part-241 Value len is 685 GET main-rest-...
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5answers
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Why does wget'ing an image give me a file, not an image?

I do wget http://services.runescape.com/m=itemdb_rs/3809_obj_sprite.gif?id=2 and it downloads the following file: 3809_obj_sprite.gif?id=2 How can I make it save as the following? 2.png
5
votes
3answers
24k views

Connect to WiFi network using Mac Terminal

Every time I try to find out how to do this, I find out how to do it on a linux, and it doesn't transfer. How do I connect to a WiFi network using Mac Terminal Bash?
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3answers
805 views

Is it wasteful to call cat?

I’m sorry if this question is really stupid, but this is basically what I have been thinking about constantly. Suppose I run: : cat ./somefile.txt A few hundred times a second. How much faster is ...
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3answers
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I want to execute the commands in a loop at the same time, not one after another

I'd like to write a loop ('for') that will do some action 'X' number of times. But instead of performing the actions sequentially, one after another, I'd like them to execute simultaneously (in ...
5
votes
1answer
768 views

Is there a way to preprocess input to bash?

I would like to be able to define arbitrary modifications to command lines that happen before bash sees them at all, ie, before expansion of any kind. Is this possible? I'm not trying to solve one ...
5
votes
2answers
2k views

Is there a face recognition command line tool?

I've download a lot of images in one directory including People and Landscape. I want to split the directory into two. I'm looking for a Linux command line tool to filter by face.
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votes
1answer
542 views

Vim process stops after executing an external command

I've been using vim recently to program in C. I have created shortcuts for compiling and running the programs from within vim itself, but recently vim's process has been stopping after executing the ...
4
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2answers
5k views

Spaces in Linux environmental variables?

Given directory: /media/foo/can haz/bar, I have tried editing bash.rc with: export Foo=/media/foo/can haz/bar export Foo=/media/foo/can\ haz/bar export Foo='/media/foo/can haz/bar' export Foo="/media/...
4
votes
3answers
230 views

Determine whether a bash script was launched by icon click or from terminal

I have a script that I want to have a different behaviour depending on whether it was launched from the terminal or by (double) clicking the icon in the file manager. Can I do this?
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votes
1answer
2k views

Open Sublime Text 2 with new tab instead of new window

I've got an alias to open files in Sublime Text 2: alias sub='/Applications/Sublime\ Text\ 2.app/Contents/MacOS/Sublime\ Text\ 2' But this spins up another instance of Sublime Text 2 (complete with ...
3
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1answer
3k views

Ping server/domain and capture its IP on Linux

With Windows, you could ping a given domain name and capture the IP as a variable, even if no reply was received. I believe the command looked something like this: ping domain.com for /f "tokens=1,2 ...
3
votes
1answer
885 views

Parse multiple HTML to text and rename as parent Directory

In a directory there are many folders .html inside, I would like all HTML parsed as new .txt with the name of the parent directory. Example1/ Index.html>Example1.txt Example2/ Index.html>Example2....
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votes
2answers
2k views

Sed replace between 2 strings with special character

I have an XML file containing a code and to use it with xmllink I need to remove a link. XML file containing: <xml version="1.0" encoding="UTF-8" standalone="yes"?> <PackingList xmlns="Link ...
3
votes
1answer
146 views

Attach command to execute when long-running thread returns

Let's say I've just started a command that will take a long time to execute, like hg clone the entire Pypy development set. Halfway through, I decide I'd like to run another process, like hg up, once ...
3
votes
1answer
5k views

Where to store bash scripts that all users may execute on Debian?

I have many bash scripts on my server, that all users may use. but it seems the location /usr/local/sbin is not the best place. I don't want to use the home directory of the users, cause ...
3
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3answers
289 views

Which files are run when I log into or reboot my machine?

I'm trying to figure out which "script" (really it's probably an "*rc" file) is running a particular command when I reboot my ubuntu machine. I've tried grepping for what is being displayed when I log ...
3
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1answer
4k views

Remove file extension in OS X using Terminal

Problem: I have some 200+ files named something in line with "DSC01852.JPG.jpg". I would like to remove the file extension so the result becomes "DSC01852.JPG". Any suggestions? I looked at the mv ...
3
votes
1answer
891 views

How to write a script to sudo the last command [duplicate]

Usually, for some commands such as apt-get install xxx, I forget to add sudo first, then I need to retype it. What I want is in such cases, I just type a simple command, for example resudo. It will ...
3
votes
2answers
960 views

Disable Bash's programmable autocompletion (based on command)

Bash in my Fedora 16 seems to autocomplete arguments based on the command itself. So if I for example type cd Tab … it will only show directories. There are however far too many commands where ...
3
votes
1answer
2k views

How to delete readonly variable in bash?

$ mySite="superuser" $ readonly mySite $ unset mySite bash: unset: mySite: cannot unset: readonly variable How can we delete mySite, as it is a readonly variable?
3
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4answers
346 views

Change directory upwards to specified goal

I'm often deep inside a directory tree, moving upwards and downwards to perform various tasks. Is there anything more efficient than going 'cd ../../../..'? I was thinking something along the lines ...
3
votes
1answer
1k views

~/.bashrc not sourced in a new lxterminal window

I added some lines to my ~/.bashrc like export JAVA_HOME=/opt/jdk1.6.0_22 I sourced it: $ source ~/.bashrc $ env | grep 'JAVA' JAVA_HOME=/opt/jdk1.6.0_22 Then I created a basic bash script under ...
3
votes
2answers
3k views

Slicing video file into several segments

I am currently using ffmpeg to slice video files. I automated the process through a script called ffmpeg_split.sh. Although this very slow it is efficient in splitting videos into equivalent settings. ...
3
votes
1answer
322 views

Force a bash script to run to completion where some items may stick

I've a Uni assignment I'm building that I need to run multiple times with multiple different parameters to check run times. At the moment I've a simple bash script that looks a little like the below - ...
3
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1answer
3k views

How can I extract only some specific folders from a tar.gz archive?

Let's say I have the archive website.tar.gz, inside is the following folder structure : home -mike -www -coolwebsite file1 file2 file3 etc. When I ...
3
votes
1answer
709 views

Can I make ssh-agent wait until I use ssh to prompt for a password?

I have ssh-agent set up to automatically start and prompt when I open a terminal window, as is explained here. It gets somewhat annoying though since many times when I open a shell I don't plan on ...
2
votes
1answer
156 views

What this command :(){ :|: & };: does? [duplicate]

What does this shell command do in Linux :(){ :|: & };: How can it be used in Denial of Service attacks?
2
votes
1answer
138 views

How to get notified when a specific file is deleted in Linux?

I'm looking for a way to monitor a file and trigger an event as soon the file was removed. Once it is removed I will replace/copy a new file and start the monitor again. E.g. watch "/tmp/...
2
votes
2answers
206 views

What does “<>” exactly mean in “echo <> temp.txt”?

Non existing file $ ls file_not_exists.txt ls: cannot access file_not_exists.txt: No such file or directory $ echo <> file_not_exists.txt $ ls file_not_exists.txt file_not_exists.txt $ cat ...
2
votes
5answers
7k views

Move all files in sub-directories to current directory?

I've got files in a bunch of subdirectories, and I'd like to flatten them out and move them all to the current directory. I found this question, but adapting the answer to: mv * . didn't work. I ...
2
votes
1answer
1k views

How to prevent terminating command to send EOF to named pipes?

The problem I faced is exactly this one: http://www.linuxmisc.com/4-linux/d7863c256bccbfb6.htm I want to be able to run a program which takes stdin, and write data to it whenever I feel like it....
2
votes
4answers
2k views

less emulate a TTY to preserve piped color output

When you pipe something through less, the program usually discards color codes because it's not outputting to a TTY. So you have to add --color=always to the options for it to work. ls -l --color=...
2
votes
2answers
6k views

Find difference with mtime - and +

Can someone explain the difference with mtime - and + switch as both are not bringing back the results I need. I'm looking to delete all files older then 5 days find /mnt/sdb1/tmp/ -type f -mtime +5 ...
2
votes
2answers
1k views

curl not uploading file to ftp

I am using curl to upload a file to ftp server. The same script is working on another system, but on this one after connecting to ftp it is not doing anything and connection times out. The detailed ...
2
votes
2answers
181 views

Unable to get profile variable using ssh

Unable to retrieve the profile variable using ssh. server2 ==> user apptst ==> bash profile has $APPHOME variable. Was trying to retrieve the value from server1 using ssh but failed. Used options ...
2
votes
4answers
754 views

Background job in bash is shutting down when the firing window is closed: how to avoid this?

You can go quickly to the question starting reading from 'Having said that' The following are details on my specific needs I'm on lubuntu oneiric and trying to create a desktop launcher to start / ...
2
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1answer
596 views

How can I remap Ctrl+C to send an interrupt signal with another key?

I've got a process in bash that I can call to stop using Ctrl+C. As far as I can see, this equals to sending an exit(1) signal. I would like to loop through these processes for a list of different ...
2
votes
1answer
4k views

Messed up $PATH variable in Mac OS X

I did something to my PATH. I was trying to add some new path and now none of the command like open ~/.bash_profile work, and echo $PATH only shows one path which is /Application/Filename. Is ...
2
votes
2answers
1k views

Remove bash startup behaviour (mac user)

When I start the terminal (which uses bash) a echoed message appears several times right before the message "You have mail." and it is added by someone that has used my computer. It also happens when ...
2
votes
3answers
1k views

Running rdesktop through a SSH tunnel in one command

I am running ssh server -L 3392:192.168.1.138:3389 in one terminal window, then running rdesktop 127.0.0.1:3392 in another to connect to a Windows machine through an SSH tunnel. How can I merge this ...
1
vote
1answer
113 views

Bash - how do you make it so that the result of a command gets placed into a variable?

For instance, let's say I wish to type the command pwd. It gives me a really long path to the current directory I am in. What I would really like to do is make it so that I can go into a completely ...
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vote
1answer
2k views

Pass arguments to osascript via shell function in OS X Mountain Lion

The answer in How to open a new Firefox window with URL argument is broken in Mac OSX Mountain Lion (10.8.2). I can't comment on that answer or question, so I had to create a new question. It fails ...
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2answers
2k views

Diff and ignore lines missing in one file

I want to diff two files and ignore lines that are present in one file but missing in the other. For example File1: foo bar baz bat File2: foo ball bat I'm currently running the following diff ...
1
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1answer
723 views

How to make cd arguments case INsensitive? [duplicate]

Possible Duplicate: Make bash’s tab-completion case-insensitive Sometimes while accessing the various directories it happens most of the times that i remember the names or at least part of the ...
1
vote
1answer
220 views

Tmux causeing issues with Bash up-arrow [duplicate]

When using tmux, I have issues of ghost characters when using the Up and Down arrow keys in Bash. If I press UpArrow a few times and then press DownArrow a few times, then the first few characters of ...
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vote
2answers
2k views

How can I clear the contents of every file in a subdirectory without changing ownership / permissions?

I can find the list of files using something like: find /path/to/files -type f And I can clear the contents of a single file with any of: > filename echo -n > filename cat /dev/null > ...
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vote
0answers
75 views

select files from a set [closed]

I need the Bash code for select file in a set of files. I use something like this find . -type f -name \*.txt to locate the set of files I want to work with. After that I would want select only the ...
0
votes
1answer
95 views

alias: extract options from command

Apologies for the bad title. I couldn't come up with a better one. I want to alias a command to another command, and extract options from the text of the command itself. I realize this is unclear, ...