A script is a sequence of commands or instructions that are executed by an interpreter program rather than compiled into a standalone executable program.

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8k views

How to check if string starts with value containing #, tab, and maybe space?

In my bash script, I want to check whether a string starts with # modified: or # new file:. In both instances, the character after # is a tab. In the latter instance, the character between ...
4
votes
5answers
2k views

Using $? in an if statement

function foo { (cd $FOOBAR; <some command> if [$? -ne 0] then echo "Nope!" else echo "OK!" fi ) } I am trying to write a function like the one above and place ...
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1answer
1k views

Can I use an if statement to detect if bash and dash are being run interactively? [duplicate]

After looking around for a while I've found several good pages describing how to check and see if a bash script is running interactively and there seem to be several methods, but one of them that I ...
7
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1answer
182 views

Is there any guarantee that /usr/bin/env will exist?

Often I will see scripts begin with a shebang line that uses #!/usr/bin/env interpreter_name for whatever interpreter, with the rationale that different systems might have the interpreter that they ...
2
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2answers
308 views

How to split files with common prefix in bash

I have a directory with many files with common prefix, like gsc*_other.foo, where * is a character that goes from 0 to 9 or a/b (where a stands for 10 and b for 11). My goal is to create text files ...
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3answers
71 views

setting up script in a linux machine for scientific computation [closed]

I'd like to setup machine for test some computation in my old laptop, before replicate the tests on the server. The computation will be image-processing and machine learning, run some program, load ...
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1answer
2k views

How to execute Netscaler commands through a remote machine via SSH connection

I have been trying to execute some NetScaler commands like "bind" & "unbind" through a Linux Box via an SSH Connection. Now the Problem is, Manually we are able to enter & execute commands on ...
2
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2answers
112 views

Using Sed with Regex

I would need to edit the values in a file delimited by colons (:) I would like to replace the contents of the file by using regular expression. After a grep to confirm that the item exist in the file ...
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2answers
65 views

Is this an array?

I'm currently looking at an existing script that have something like this: variable='val1 val2 val3 val4' Is this another way of setting an array? If not, what is it?
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7answers
7k views

Using notify-send with cron

I am using Arch Linux with KDE/Awesome WM. I am trying to get notify-send to work with cron. I have tried setting DISPLAY/XAUTHORITY variables, and running notify-send with "sudo -u", all without ...
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2answers
10k views

Human readable dmesg time stamps on OpenWRT

The output of dmesg shows the number of second+milliseconds since the system start. [ 10.470000] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver [ 14.610000] device eth0 entered ...
4
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5answers
4k views

Bash Script to Sort Files into Alphabetical Folders on ReadyNAS Duo v1

I have an old ReadyNAS Duo v1 (Sparc) running an unknown flavour of Linux. I have a folder structure with 1,000+ files I want to move into a folder structure based on the first letter of the file ...
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4answers
327 views

Prefixing and appending blocks of text to a list of files

I'm trying to prefix and append blocks of text to a list of files. Here is where I am so far. The sticking point is the sed -i "1i \$prefix" "$file" && line. sed won't substitute the value of ...
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1answer
774 views

automatic capturing top output by cronjob CENTOS 6.5 x86_64

I have this command: top -n 14400 -a -b -d 1 > /toplogfile.txt I want to make a script which is run by cron every day to capture top output, and if it is possible gzip the output file after the ...
1
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1answer
175 views

Bash: show prompts if arguments weren't provided

What is the best way of supporting in the script prompts and arguments at the same time? I want to show prompts if arguments weren't provided. Is there something better/shorter than this? ⇩ ...
6
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1answer
741 views

Bash is automatically reloading (injecting) updates into a running script upon saving it: Why? Any practical use?

I was writing a bash script, and happened to updated the code (saved the script file to disk) while the script was waiting for some input in a while loop. After I returned to the terminal and ...
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2answers
2k views

Bash script to adjust brightness when battery unplugged

I am trying to set up my system and to get some practice with scripting and the like. I am running Linux Mint 16 on a Samsung RC520 laptop (Linux 3.11.0-12-generic x86_64). I want to implement a ...
4
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0answers
345 views

GRUB 2 scripting: convert device name in GRUB notation into a Linux device name

I'm trying to use partition labels (or UUIDs, that does not matter) to select root partition without use of an initrd/initramfs. With initramfs, this is fairly easy: root=LABEL=... or ...
2
votes
2answers
790 views

Number of cores on FreeBSD

What would the equivalent of Debian's nproc be in FreeBSD? I'm trying to include this in a bash script variable so if it could just print out the number of cores that would be fantastic.
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3answers
1k views

How to compact a chmod UNIX command

Is there anyway to compact the follow UNIX command: chmod 755 scriptA.ksh | chmod 755 scriptB.ksh | chmod 755 scriptC.ksh | chmod 755 scriptD.ksh The above command makes every KornShell (ksh) ...
15
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3answers
2k views

Send email written in markdown using mutt

Sometimes I need to send a fragment of code on google-group inline. Text does not help here; I can type it in markdown, convert it to html (using pandoc etc.), attach to mutt as text/html and send it. ...
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0answers
69 views

Automating startup tasks

I have a "morning ritual" that occurs on every boot of my machine: starting up a few browser tabs, starting up skype, starting up terminator and subdividing some screens, etc. Is there any tool that ...
6
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1answer
14k views

Linux - Sending a command to a screen through a shell script? [duplicate]

I'm trying to figure out how to make a script that will be able to send commands to a screen that will execute within whatever the screen is doing. Is this possible, and if so, how is it done? I've ...
1
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1answer
178 views

Linux - How to open a console and display command results on startup?

I have a Linux server with a screen always displaying the end of a very usefull file. How could I automatically enter a shell and display the end of this file when the server starts? I'd like to do ...
2
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1answer
2k views

How can you run a script triggered by a joystick input?

I'm using a Raspberry Pi running Raspbian to power my arcade cabinet. I want to shut the Pi down using the sudo poweroff command without using the keyboard. I'm thinking the best way would be to ...
43
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5answers
53k views

Using while loop to ssh to multiple servers

I have a file servers.txt, with list of servers: server1.mydomain.com server2.mydomain.com server3.mydomain.com when I read the file line by line with while and echo each line, all works as ...
2
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1answer
3k views

permission denied on scripts in ~/bin

I set some additional locations to the PATH environment variable in my ~/.bashrc so that these are included/sourced in logins and non-interactive scripts that are scheduled with cron. I've noticed ...
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3answers
92 views

Copying specific text from one file into a schema

I have two files. One being a schema, and the other a list of data. The schema looks like: line_name: shot_edit: channel edit: cable_edit and repeats regularly for the number of lines that I ...
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4answers
8k views

How can I print only certain commands from a bash script as they are run?

I have a bash script with various if statements based on command line arguments I pass in when calling it. Having some kind of output as to what commands are being run is helpful to confirm the flow ...
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2answers
1k views

How can I make awk on Busybox treat the entire input with NULL character in between as a single record?

I wrote a base64 encode script for my Busybox system. #!/bin/sh base64encode() { /usr/bin/awk -- ' function asc(char,l_found) { l_found=0; for (i=0;i<=255;i++){ if ...
17
votes
1answer
6k views

apt-get install without debconf prompt

I would like to install chef via apt non-interactively, but by default, apt installation brings up this prompt: Is there a way to skip this step during installation or pass a value to apt install? ...
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2answers
818 views

Convert perl script to bash

The following script it's about monitoring some logs, the $timestamp is at log at every line that something happens. Example: 03:19:13.4 Begin summary update for ...
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3answers
1k views

securely automating a script which requires a key to do its task

I have a script that downloads bank transactions to store in a database. To get these transactions requires a password for each account. The database is encrypted and requires a key to access it. All ...
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5answers
13k views

Understanding boolean operators in bash script

phone_missing=false echo "missing $phone_missing" if [ ! $phone_missing ] then echo "Lost phone at $readabletime" $phone_missing=true fi I just can't wrap my head around this, as ...
1
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1answer
188 views

How to script this task?

First of all, I can make basic use of the linux command line, but have slim to none experience with shell scripting. What I want to do: I have a router running OpenWRT, a destop pc and an Android ...
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0answers
48 views

script works fine on client machine but doesnt work in nagios

purpose: nagios check for kannel stuck Date : dec 8, 2013 /etc/init.d/kannel status | grep -i -E "SMS: received" | awk '{ print $3 }' > kannel_temp_1.txt /etc/init.d/kannel status | grep -i -E ...
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4answers
5k views

Intersection of two arrays in BASH

I have two arrays like this: A=(vol-175a3b54 vol-382c477b vol-8c027acf vol-93d6fed0 vol-71600106 vol-79f7970e vol-e3d6a894 vol-d9d6a8ae vol-8dbbc2fa vol-98c2bbef vol-ae7ed9e3 vol-5540e618 ...
1
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1answer
12k views

How to reassign new values to array elements?

I'm trying to figure out like three or four things at the same time.The most I need help with is how to get the greatest number in all the files that I have created on a prior run of my script, that ...
14
votes
4answers
26k views

How can I suppress output from grep, so that it only returns the exit status?

I have the grep command. I'm searching for a keyword from a file, but I don't want to display the match. I just want to know the exit status of the grep.
4
votes
3answers
481 views

Bash: handling “[[ statement ]] || echo problem found ; exit 1” logic

In the statement in the title, there is a problem that even if the statement is true, it will still exit with status 1 because, as I understand it: [[ statement ]] || echo problem found ; exit 1 ...
1
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0answers
61 views

List Mails by subject

I'm writing a script to send mails from a mailbox on a remote server and a script to check if the mails are received at another remote server. For this I have configured mutt. What I now need is to ...
1
vote
2answers
142 views

Command working from CLI but not from script

I have a command that I use from the CLI to properly color files, folders, executables, etc. The command that I'm executing looks like this: test -r ~/.dircolors && eval "$(dircolors -b ...
1
vote
4answers
3k views

How do I delete files with spaces in them in bash script?

this is a three part topic to a two part process that still is not working for me: Objective: to manipulate a filename then delete it the filename has spaces between the words then the dot .ext ...
2
votes
1answer
3k views

Using BASH versus ASH on Synology

The majority of my photo files have the following naming convention / format IMG_20131204_120000.JPG, showing date and time the photo was taken (iPhone/Apple naming convention). However, not all my ...
6
votes
5answers
25k views

Parsing a delimited text file in bash as command arguments

I have a text file split up like so: field1,field2,field3 xield1,xield2,xield3 dield1,dield2,dield3 gield1,gield2,gield3 Each of these columns will be a parameter to a program, and I would like ...
1
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3answers
118 views

Automating pipes?

I find myself using basically the same line over and over again: cat file | command1 | command2 | command3 > file Is there a way I can put all these pipes into one script, so I can just run ...
2
votes
1answer
46 views

Why does combining `less` and `script` disrupt line endings?

This bash snippet will print out the numbers 1 to 10: $ for i in $(seq 1 10); do echo $i; done 1 2 3 4 5 6 7 8 9 10 When I try to use this with script and less like so: $ script -q -c 'for i in ...
7
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1answer
1k views

How to maximize a window programmably in X Window?

I'm wondering if there is any commands or programs to make some window maximized in X Window? For example, what I imagine is something like this xmaximize -window *window_id*
3
votes
2answers
15k views

script to automate scp in network

I have a network full of Linux machines. In this network, I have a user as user1 with the password as password in all the machines. I have the following script to put files in the home directory of ...
3
votes
3answers
212 views

Collect EXIF data of a directory

Is there a way to extract EXIF information of all images within a directory (into an output file)? Preferably I also need GPS data but this is not essential. I only ask, as I have a number of ...