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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0
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0answers
32 views

Calculate Total disk i/o by a single process [duplicate]

I am looking for some tool that will dump total disk I/O by a single process after it ends. So far my finding is :- iotop= It shows i/o per process in real time but does not give total after process ...
0
votes
1answer
40 views

Syntax error in bash script: near unexpected token `else' [closed]

#!/bin/bash input="" echo "Does a wall needs to be sent?" read input if [ $input="yes" ]; then echo "Sending message to all users" echo "" else if [ $input="no"]; then exit fi fi echo ...
2
votes
3answers
46 views

bash - extract filenames from html file containing multiple links

I have downloaded an html file autogenerated by a script on a webpage. The file contains multiple links, including links to images I am trying to extract the full names of the images, for example ...
0
votes
0answers
25 views

-bash: android: command not found

I'm on a Mac running Mavericks trying to learn how to develop Android apps (in the process I'm learning bash too). To run on the emulator they suggest the command android avd. I always get the error ...
3
votes
3answers
115 views

Is the output mixed like this because of xargs and how can I fix it?

I'm learning a bit of Bash by using xargs to list whois records for a bunch of IP addresses. The command used is: echo "$1" | tr "\n" "\0" | xargs -0 -n 1 -t -P 3 -I % sh -c 'echo "\n 44rBegin whois ...
3
votes
2answers
29 views

Comparing an string by value of a floating number to a number

I wrote the code below: for j in `cat output_10.txt` do dri=`echo $j |cut -d':' -f1` nu=`echo $j |cut -d':' -f2` tot=`echo $j |cut -d':' -f3` fre=`echo $j |cut -d':' -f4` if [ $fre > 2 ] ...
1
vote
2answers
49 views

Merge csv files with conditions

I have 2 CSV files for each date (csv_2014_4_15 and csv_2014_4_16) , with basic structure and couple of unique columns as below. id,name,created_at,updated_at,other columns 12, joe, 2013-1-1 18:30, ...
1
vote
1answer
23 views

How to slice a text file into several files of 100 lines each? [duplicate]

My question might be quite unclear here. I have a giant text file with values that looks like this 0.00601233 0.000139403 0.000133679 0.000139497 0.000141683 0.000141888 0.000138646 0.000133465 ...
2
votes
3answers
147 views

in bash, read after a pipe is not setting values

Edit : original title was "read fails in bash" With ksh I'm using read as a convenient way to separate values: $ echo 1 2 3 4 5 | read a b dump $ echo $b $a 2 1 $ But it fails in bash : ...
3
votes
1answer
33 views

Why does the read command not take interactive options when run by sh?

I want to download a provisioning script that reads some configuration parameters via read, and execute it: curl http://example.com/provisioning.sh | sh The problem is, that the read command in the ...
3
votes
2answers
135 views

using “ifne” in Bash pipe

In my script, I am using the ifne utility from the moreutils package. The line can be simplified to the following: printf "asdf\n" | ifne cat - && echo "stream not empty" ifne only ...
2
votes
2answers
22 views

Writing content from a file to another file on set time intervals using delimiters

I'm trying to write a script in bash that reads a file file1 and writes to another file file2 every 2 seconds, which is easy enough. However, I want to write to file2 on either a line by line basis ...
2
votes
1answer
31 views

Controlling bash script concurrency, flock inheritance

I have a bash deployment script that handles deploying updated code to a Tomcat instance on CentOS, however, both Chef and RunDeck may invoke the script, and since Chef runs periodically there is a ...
1
vote
1answer
38 views

Why does the same sed regex (after grep) fail when run in a bash script vs bash command line?

Here's the script. It is successful when I run it from the BASH prompt, but not in the script. Any ideas? When I say "fails," I mean the sed regex doesn't match anything, so there is no replaced ...
10
votes
3answers
595 views

Is there any major difference when comparing a variable as a string or as an int

Out of curiosity, when doing a bash variable comparison (its value being an integer) it's possible to test it against some predefined value either declared as an int or as a string. Sample script: ...
0
votes
2answers
56 views

How to count number of instance of a word starting at another word

I need to grep the MySQL-error log starting at today's date formatted like: `date +"%y%m%d"` (140710) And look for all instances of the word partitioned. I've tried various things to no avail. ...
1
vote
0answers
40 views

Sourcing nested sourced bash script multiple times causes an infinite loop [closed]

I have a cronjob that sources a configuration file, so as to put some variables in the environment, and then runs a script. This config script sources another more general config file that sources ...
4
votes
3answers
147 views

Adding comments using 'set -x'

Sometimes it is really handy to just add set -x to the top of your script to show all commands before they are executed. There is only one drawback creating scripts with a decent output: I don't ...
3
votes
6answers
135 views

ls content of a directory ignoring symlinks

I have a directory in which I would like to list all the content (files and sub directories) without showing the symbolic links. I am using GNU utilities on Linux. The ls version is 8.13. Example: ...
1
vote
2answers
61 views

Configure bash and/or vim to execute source ~/.bashrc everytime I finish editing it

I would like to execute source ~/.bashrc every time I finish editing a file with vim (i.e. after :wq vim command). How should I configure vim or bash to work that way?
1
vote
1answer
55 views

Searching history forward after backward?

In bash, when I hit Ctrlr, I can search the command history backward. If I would like to search forward again, what shall I do? I hit Ctrls, but it doesn't work. My bash is GNU bash, version ...
1
vote
3answers
63 views

sed - replace string with file contents

I have two files: file1 and file2. file1 has the following contents: --- host: "localhost" port: 3000 reporter_type: "zookeeper" zk_hosts: - "localhost:2181" file2 contains an IP ...
5
votes
4answers
93 views

Have xargs use alias instead of binary

Bash 4.2 on CentOS 6.5: In my ~/.bash_profile I have a bunch of aliases, including: alias grep='grep -n --color=always' so that I can get color highlighting and print line numbers automatically ...
1
vote
3answers
89 views

How to escape special characters in a string?

Assuming $file holding a value of a file name, say Dr' A.tif. In bash programming, how could I escape single quote and any other special character of the $file without removing the special character? ...
3
votes
1answer
31 views

Matching several patterns on one line

I often use a program called tty0tty, which creates a null modem using PTYs. Now I want to make it part of an automated process. When I start tty0tty it prints (/dev/pts/1) <=> (/dev/pts/2) ...
2
votes
1answer
32 views

Using xargs with git

I am trying to practice using xargs. I tried the following, passing the SHA1 via xargs: $ git show SHA1 --name-only I also tried: $ git log --author=jim --grep="patch" |head -n 1|cut -d ' ' ...
2
votes
1answer
74 views

Bash script and processes

I have created a bash script for use with a graphical bar in Linux, however the script seems to spawn too many processes. The script: #!/usr/bin/bash executable="/usr/local/bin/bar" monitor=${1:-0} ...
1
vote
1answer
37 views

Control + L not clearing screen

When I try to clear my terminal screen on OSX: computer@ ~ () $ ^L And when I hit Enter after that it just shows: -bash: : command not found Any ideas on how this happens? My .bash_profile, ...
4
votes
1answer
52 views

Create map network_iface_name <--> IPv4 address

I'd like to implement a bash script that creates a mapping between the network cards (or interfaces) names in my computer and their IP address (in CIDR format, if possible). The goal is having ...
5
votes
2answers
116 views

Is there a way to make this one-liner faster?

Context I have a directory of thousands of zip files that are dated in the form YYYYMMDD_hhmmss.zip and each about 300K. Within each zip file is about 400 xml files each about 3K. The problem I ...
2
votes
2answers
157 views

Store all dates in a given date range into a variable

I want to store all possible dates between two user input dates. The input will be as like 20140605 and 20140830. I want to store every date between the given dates into a variable using a loop so ...
6
votes
2answers
164 views

Batch rename image files by age plus add date and variable to filename

The question is completely rewritten due to things learned from the first two answers and comments that I was unaware of when first asking. After a photo shoot I come home with files that look like ...
2
votes
2answers
26 views

How can I quickly return back to the last working directory? [duplicate]

All too often I find myself cycling between two directories to perform different tasks. The directories don't always have an easy-to-use relative path between them. As a result it is quite cumbersome ...
2
votes
0answers
19 views

Running Custom commands in a Terminal Application [duplicate]

I'm running a terminal application in /dev/pts/X terminal that has its own console as:         What I need is to run commands specific to this application but from ...
2
votes
1answer
53 views

bash + Is there something like log4j for bash script?

Is there something like log4j for bash script? I would like to be able to treat errors differently based on their severity. For example, log4j allows me to differentiate between errors, info, debug, ...
3
votes
0answers
109 views

bash does not autocomplete my command when using sudo?

I'm using SaltStack. I would like to auto-complete the minion name when calling salt command. The following line has been added into ~/.bashrc: complete -o default -o nospace -W "$(sudo ls -1 ...
5
votes
1answer
163 views

Test -n gives unexpected result

I understand test -n <expression> to return false if the expression evaluates to a string length of greater than 0. Why then does the following happen? Macbook:~ echo ${#undeclared_variable} 0 ...
0
votes
1answer
41 views

Using getopts to parse options after a non-option argument

I have a bash script as below in a file nepleaks_upd.sh, that I want to run as ./nepleaks_upd.sh bootstrap --branch off. Couldn't make it to take --branch , but what it works with is ./nepleaks_upd.sh ...
6
votes
5answers
227 views

Strategy to extract movies's name from this ununiform dataset?

I am working on a movie database problem to improve regular expressions, this is the problem I'm running into. My dataset looks like this: Movie Name (variable space and tabs) year Movie1(can ...
28
votes
5answers
696 views

How to save a command you entered without executing it? [duplicate]

Every Linux user has experienced this annoying thing: you begin typing a long and boring command, then realise you should have executed another one before. How to save the first one to execute it ...
4
votes
3answers
189 views

How can I delete a trailing newline in bash?

I'm looking for something that behaves like Perl's chomp. I'm looking for a command that simply prints its input, minus the last character if it's a newline: $ printf "one\ntwo\n" | ...
4
votes
2answers
383 views

write a line before it is executed without writing it twice

I write a bash script with a --verbose option, where I want to write most lines before I execute them xinput --set-prop "$TP" "Device Accel Constant Deceleration" $TOUCHPAD_DECELERATION I would ...
2
votes
1answer
35 views

Bash for loop create folders; do I have to escape some chars?

I want to create 5 files with the same name but with an incremental counter. If I do: for i in {1..5}; do touch hallo_$i; done I get hallo_1, hallo_2, hallo_3, etc. If I do: for i in {1..5}; ...
1
vote
1answer
22 views

default argument parsing section

I created a bash script where I would like to add a help options like -h, --help, --verbose and some others. If I create it like described here Will this be a standard solution? # Execute getopt on ...
2
votes
0answers
46 views

Bash tabcomplete file names for environmental variable values

After I upgraded my Ubuntu from 12.04 to 14.04, bash would no longer let me tabcomplete file names when setting the value of an environmental variable, e.g. FILE=/home/_ _ is where I would press ...
0
votes
2answers
67 views

Convert json mapping object to managed csv row using bash script

I have json mapping under properties key as below in a file Customer.json, { "customer": { "properties": { "customerId": { "type": "string", ...
0
votes
2answers
98 views

How do I enable &>/dev/null by default for all sh/bash commands?

Is there a way to make &>/dev/null the default behavior in a sh/bash script? I' rather not have to appended this to every command within the console, not an *.sh script. I'm looking to make a ...
12
votes
3answers
283 views

Using variables to store terminal color codes for PS1?

In my .bashrc, I use ANSI terminal color codes to colorize various bits. It looks like this: PS1='\u@\h:\w\[\033[33m\]$(virtual_env)\[\033[32m\]$(git_branch)\[\033[0m\]$ ' where virtual_env and ...
14
votes
2answers
404 views

How do I start all shell sessions in a directory other than $HOME?

When I open my non-login shell in Ubuntu, my present working directory is /home/user_name (my $HOME environment variable), but I want to change this such that when I start my terminal I am in some ...
2
votes
2answers
47 views

Remove files and directories even if not empty, except some directories

I am trying to remove all contents of a directory with some exclusions. I'm currently using this: find . -type f | grep -vZf ../../exclude.file | xargs rm -rf The exclude.file contains: *log* ...