Questions about bash only, as opposed to other Bourne/POSIX shells. For all Bourne/POSIX-style shells, use the /shell tag instead.

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4
votes
2answers
3k views

Use `ln` to create a missing directory

So I'm writing a small package manager, and a problem I've run into is making the symbolic links to files. It installs the package to /usr/pkg/name-version, and then reads a file to determine what ...
2
votes
4answers
712 views

Stripping all vowels but the first from a set of strings

I have a string comprised of multiple substrings, separated by underscores. For example: AbcdAEfd_hEgdgE_AbAAAAA. I need to remove all vowels except the first from each substring. So: AbcdAEfd -> ...
13
votes
6answers
14k views

Terminating an infinite loop

I have a command that I want to have run again automatically each time it terminates, so I ran something like this: while [ 1 ]; do COMMAND; done; but if I can't stop the loop with Ctrl-c as that ...
6
votes
1answer
6k views

export HTTP_PROXY and special characters in passwd

Suppose for the sake of argument my password below is abc123@ I need to authenticate my linux machine through a corporate proxy to get patches and updates... normally I'd use this: export ...
6
votes
3answers
546 views

Bash autocomplete gives different file name than ls

An incredibly strange thing just happened. Through a serious typo, I entered cp filename.xsl .^?~ Yeah, that's right, dot-caret-questionmark-tilde! Truth is stranger than fiction. It gets weirder. ...
1
vote
3answers
880 views

Error in Script. Command find is skipping folders with space character

I need a script that counts the files in a directory (and sub). I've taken the followed script, and changed it to my need. It works like it should, except for folders with space characters. I'm ...
3
votes
2answers
5k views

SSH + Sudo + Expect in Bash script: Run command with sudo in remote machine

I am trying to automate the deploy of some .deb packages with an script. I want to execute sudo dpkg -i $myDeb.deb in a list of remote machines I can access with ssh. I've tried to automate the ...
5
votes
2answers
798 views

Wrapping a shell script with tee

There is a bash script which prints some logs and allows some arguments. The script prints the logs to STDOUT. Let's say the script's name is AAA.sh I'd also like to make the script to print the logs ...
4
votes
2answers
340 views

Exiting a pipeline if a former command fails

I'm trying to check the number of running and queued PBS jobs by parsing the output of qstat -tn1 from a bash script. So far, this has worked: count () { qstat -tn1 | awk ' BEGIN { R = 0; ...
1
vote
2answers
155 views

Create a series of increasingly larger files

I need to test an sftp host for its cutoff of file size upload limitation. I wanted to make a series of files that were of increasingly larger sizes, to try to upload them all and see where they ...
1
vote
2answers
1k views

random number needed

I need a command line script that will generate a random integer between 1 and 6. I'm using Ubuntu with bash. I was working on this a couple of months ago using 'bc', but never got it to work ...
2
votes
0answers
382 views

A problem with mknod when logged in as root

I am trying to load a char device driver written by myself. To achieve this I use a modified bash script published on this site: http://www.makelinux.net/ldd3/chp-3-sect-2. Here is my version of the ...
2
votes
2answers
25k views

How to set environment variable JAVA_HOME that will be saved on exit? [duplicate]

Possible Duplicate: How do I set a user environment variable? (permanently, not session) I use Suse. First was installed jdk7, so JAVA_HOME remains like: /usr/java/jdk1.7.0_05/ After I ...
0
votes
2answers
3k views

How can I rename all files in the current directory having a particular extension to another extension? [duplicate]

Possible Duplicate: Renaming multiple files (changing extension) Suppose that in my current/working directory I have five files: file1.xvg file2.xvg file3.xvg file1.eps file2.eps Is ...
8
votes
3answers
31k views

How can I delete all files with a particular extension in a particular folder?

If I set the current/working directory (navigating to it using cd) to some particular directory and then type: rm *.xvg What will this command do? Is it true that the above command will only delete ...
0
votes
2answers
1k views

Re-assigning (specifically, incrementing) a variable in a bash script [duplicate]

Possible Duplicate: How can I do command line integer & float calculations, in bash, or any language available? I would like to simply re-assign a variable (to be specific, increment it ...
5
votes
4answers
1k views

Is there a difference between these two commands?

cat a > b and cp a b If they are functionally the same for all intents and purposes, which one is faster?
4
votes
2answers
500 views

How can I get awk to print both matches and non-matches?

Basically, all I want to do is alter outputs if the input matches a filter, but the part being altered isn't what is being filtered (or I would use sed). The problem so far is that my awk is only ...
5
votes
2answers
615 views

Automate workflow in shell

Coming from GUI interfaces I've come to finally understand the power of having everything piped in text, but I don't really know how to use all that power yet. I realized the workflow for a ...
4
votes
2answers
2k views

delete first line of file only if blank using sed

I have a solution for this in awk: awk '{if (NR==1 && NF==0) next};1' somefile but was unable to find one that worked in sed. E.g., sed -i.bak '/^$/{1,1d;}' somefile ended up deleting ...
12
votes
2answers
767 views

Keep only successful commands in BASH history

Sometimes I misunderstand the syntax of a command: # mysql -d test mysql: unknown option '-d' # echo $? 2 I try again and get it right: # mysql --database test Welcome to the MySQL monitor. mysql ...
22
votes
4answers
25k views

How to copy some, but not all files?

So, you can use the * as a wild card for all files when using cp within context of a directory. Is there a way to copy all files except x file?
1
vote
1answer
227 views

How to find/correct error in a path

It's often that a long path is mistyped or you get a log file entry that a path does not exist. Is there a command or shell function that navigates the path hierarchy until it finds a matching path? ...
10
votes
3answers
6k views

How to sort the string which combined with string + numeric using bash script?

This is the data what I want to sort. But sort treats the numeric to string, the data it no sorted as I expected. /home/files/profile1 /home/files/profile10 /home/files/profile11 ...
2
votes
6answers
416 views

bash equivalent of this use of tcsh “sched” command?

In tcsh, the built-in sched command causes a command to be executed by the current shell at a specified time. I have the following $HOME/.sched file (this is a simplified version of it): setenv ...
6
votes
7answers
4k views

How to create a testcolor.sh like the following screenshot?

I found this image on the internet, but don't know how was it made, Can anyone provide a sample on that? I just would like to have a color table as well.
3
votes
6answers
3k views

Text file look-up by column

I have a file in this format: [#] OWNER_NAME NAME SIZE [6] Robottinosino Software 200 [42] Robottinosino Ideas worth zero 188 [12] ...
10
votes
2answers
1k views

Two different /etc/hosts depending upon the time

I am trying to make a productivity suite for myself. My first goal is to block Facebook, Gmail and Stackexchange from 0900 to 1600. As of now, I have edited my /etc/hosts and added 0.0.0.0 ...
3
votes
2answers
2k views

Bash script doesn't work as cronjob

I'm trying to get this simple bash script to work within a cronjob. It's used to generate static nginx webserver statistic pages using GoAccess. I tried everything I know to resolve this issue, it ...
15
votes
2answers
5k views

Rule for invoking subshell in Bash?

I seem to misunderstand the Bash rule for creating a subshell. I thought parentheses always creates a subshell, which runs as its own process. However, this doesn't seem to be the case. In Code ...
5
votes
1answer
351 views

Is split-screen `cat`ing possible?

I asked the question How to use cat or less depending on the line count? with the intention of browsing many files without having to scroll up too far to view my history after displaying a long file, ...
1
vote
4answers
4k views

How to unrar and unzip files recursively?

I have a huge file that contains zips and rars with zip and rar files located within on a linux box. I basically need a script or one-liner that will recursively hunt through the directories and ...
7
votes
1answer
2k views

Variable substitution with an exclamation mark in bash

I have the following lines in my .cfg bash script file DDF_SOURCE="siebel_DATA_DATE_FORMAT" DATA_DATE_FORMAT=${!DDF_SOURCE} how is ${!DDF_SOURCE} evaluated? It would be !siebel_DATA_DATE_FORMAT, ...
14
votes
2answers
6k views

How to Extract Album Cover Image from MP3 file?

I have a bunch of MP3 files that have their album art included within the file itself. I am now looking for a way to extract them to store them separably, at best from command line. Is there a way to ...
3
votes
3answers
192 views

Exporting just a single file

To make scripts accessible from anywhere in the terminal, one can use the following sequence of commands: PATH=$PATH:some_path_here export PATH Which includes all files at the path sent in ...
8
votes
2answers
9k views

Loop through tab delineated file in bash script

Here's what I have so far: #!/bin/bash while read line; do DB=$(echo $line | cut -f1) USER=$(echo $line | cut -f2) PASS=$(echo $line | cut -f3) echo DB=$DB USER=$USER ...
7
votes
3answers
6k views

Multivariable For Loops

Is there a way to specify multiple variables (not just integers) in for loops in bash? I may have 2 files containing arbitrary text that i would need to work with. What i functionally need is ...
2
votes
4answers
2k views

chown all files based on file name pattern in current directory

I'm trying to chown all files whose filenames begin with ChownFileNames. I've used this command, but it doesnt seem to work: find . -maxdepth 1 |grep 'ChownFileNames*' -exec chown hadoop:hadoop -- {} ...
3
votes
1answer
2k views

Make awk use bash with the system() command

Is there a way to make awk use bash instead of sh when running system commands using the system() call? I want to use some bash-specific features such as [[ ]] and < > string comparison operators: ...
7
votes
2answers
659 views

Shell Script for going through a dir recursively and chmodding based on conditions of file type

Can anyone point me to either code or a tutorial for writing a shell script that can recursively go through an entire directory structure (starting at the current working directory, or given an ...
4
votes
1answer
2k views

How do I preserve the history file of cygwin bash across independent sessions?

So my home directory does have a .bash_history file, but it refuses to grow any bigger for some reason. I've already changed the .bashrc settings to set the history size to 99999 and the history file ...
2
votes
4answers
2k views

Run if statement on remote machine

I'm trying to run a set of commands on a remote machine, that includes an if statement. I'm using this to shutdown a list of kvm instances. The first line should be fine, but could be prettier, rest ...
6
votes
2answers
2k views

SSH LocalCommand on exit

In ~/.ssh/config you can use the LocalCommand directive to execute a local command whenever you connect to a remote machine via SSH. But how do I execute a command when I exit an SSH connection? It ...
1
vote
2answers
616 views

Bash script to ftp only files of type gz in current directory

I have a bash script that cd to the right directory then uses the mput command to ftp all the files in the directory to a remote server, as below: for from_dir in $DATE_LIST do cd ...
1
vote
2answers
2k views

How to execute a function in the .profile file

I have a function which is supposed to remove duplicate copies of directories from my PATH environment variable. I have created some duplicates so I can test it but I don't know how to: 1) put the ...
4
votes
2answers
3k views

Bash Linux random CLI Password generator and `<`

I recently discovered this method for generating a 9 character password from the linux prompt in bash: < /dev/urandom tr -dc A-Za-z0-9_ | head -c9 What is < doing?
139
votes
16answers
81k 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, ...
24
votes
12answers
6k views

Remove duplicate $PATH entries with awk command

I am trying to write a bash shell function that will allow me to remove duplicate copies of directories from my path environment. I was told that it is possible to achieve this with a one line ...
4
votes
3answers
2k views

Opening a PDF file by typing its name

I am on Mac OS X and I usually open PDF files from the terminal (using bash) open myfile.pdf Now I'd be able to type only myfile.pdf and have that opened with the command above. Is there any ...
32
votes
3answers
16k views

What is the difference between ~/.profile, ~/.bashrc, ~/.bash_profile, ~/.gnomerc, /etc/bash_bashrc, /etc/screenrc …?

Answers to the questions on SO and askubuntu, along with poking through (and reading headers of) $HOME and /etc/, indicate a number of files that can be used to set environment variables, including: ...