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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What does “FILENAME=$(echo $INFILE | grep -oE ”[^/]+$“) ” mean?

FILENAME=$(echo /root/Source/code/script.sh | grep -oE "[^/]+$") I know that it would give me the file name from the file path here as script.sh. But can some one please explain me this?
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2answers
344 views

Using grep to find first two numbers of IP addresses?

I'm trying to figure out how to use grep to pull out only the first two numbers of an IP address in a list. I've got a routine that is isolating the log entires (from Exim) that I need, now I just ...
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2answers
115 views

How to notice log file changes with Linux standard tools? [duplicate]

I need something that does not need to be installed. It's on an embedded system with very little space on the HD. I can't instal anything. I need to do it with something that is already included. I ...
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3answers
561 views

Shell Script to move folders containing a specific word

I'm searching for an simple shell script to mv all folders in /var/www/uploads/ that containing Math or Physics in the name to /mnt/Backup/. I've never done something like that before, due to the ...
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1answer
88 views

Prompting when redirecting content of script to remote machine

I have simple script: #!/bin/bash while getopts ":u:" opt; do case $opt in u) USER="${OPTARG}" ;; \?) echo "Unknown flag has been used: -$OPTARG" >&2 exit 1 ...
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3answers
226 views

shell script problem with using the operators

I am comparing two strings using the levenshtein distance algorithm. I got the PHP implementation of the algorithm from here. I am calling this php implementation from my shell script as below. ...
3
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1answer
1k views

Differences between %pre and %post in Kickstart on CentOS?

I have been setting up machines with Kickstart on CentOS and I am unsure about the differences between the %pre and %post sections of the kickstart .cfg file. The CentOS Documentation for the ...
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1answer
369 views

Parallel execution of bash script

I have a table URL_Experiment in my database (mySQL database). I have 2 million URL links in this table. For each URL, I am checking if some particular text is present in the URL and updating the ...
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1answer
97 views

Need to grep for specific lines from ongoing log and save it in some file

So, let me start with the overall outcome that i want to achieve. There is just one log, which will have info on certain devices, that i am upgrading. I use "tailf log" to monitor the log. Now, ...
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1answer
51 views

Pressing tab after sourcing script file prints script related output

I have a script file in a directory. Its contents are as follows : #!/bin/bash ...
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1answer
111 views

print all values of a file after removing some characters using grep

I have a file in which the values are stored as below. Assistant Professor at SASTRA University St John's memorial college Paul George Univeristy Department Chair at University of Texas I am ...
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3answers
1k views

Extracting characters after a particular text

I am extracting a page from website using cURL command. curl "www.google.com" -s | w3m -dump -T text/html > foo.txt The w3m command outputs the HTML page in a much more simpler format so that ...
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1answer
396 views

shell script construct array for file elements

I have a file named input_file which contains some lines. I need to remove certain characters in the line and store them in an array. So to remove the characters, I use the sed command and storing in ...
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2answers
110 views

Make Trickle get the correct $PATH

Trickle is a bandwidth limiting program. I have the following script for trickle. #!/bin/bash echo $PATH trickle -s -t 3 -u 200 -d 200 "$@" I have a script in ~/bin/ that want to run the script ...
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1answer
5k views

curl and grep commands output into a new variable

I am extracting information from a website. I designed the code in VBA and found that it is taking too long to execute. So, I have decided to rewrite the code in Unix script. I am extracting a page ...
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1answer
314 views

What's the safest way to pipe an email to a script via procmail?

I have a simple procmailrc recipe that hands mail off to a script: LOGFILE=/home/foouser/procmail-log VERBOSE=yes MAILDIR=/var/spool/mail/foouser DEFAULT=/var/spool/mail/foouser SHELL=/bin/sh ...
2
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1answer
80 views

Why does AWK not like dots in one of two substitutions?

I'm trying to use AWK in a bash script to look for a placeholder string in a template file and replace it with the contents of a variable that (can) contain various special characters. Example: ...
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2answers
8k views

Use awk to split line into array and use that array's values in calling shell

I am trying to use awk inside a bash script and do a rather common task: iterate well structured file lines and split them by a delimiter into an array. Here is a sample from the file: ...
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1answer
99 views

why does the dollar sign cause this command to be executed?

test_script.sh: #!/bin/sh D1="$(dirname $0)" echo $D1 D0="(dirname $0)" echo $D0 What I type on the command line: $ ./test_script.sh Output: . (dirname ./test_script.sh) What significance ...
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2answers
3k 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 ...
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5answers
1k 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
627 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 ...
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1answer
115 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 ...
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2answers
148 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
48 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
1k 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 ...
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2answers
95 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
56 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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3answers
3k 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
4k 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 ...
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4answers
2k 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
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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
332 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 ...
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1answer
99 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
412 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
1k 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
155 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 ...
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1answer
225 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
969 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) ...
10
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3answers
1k 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. ...
2
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0answers
64 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 ...
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1answer
5k 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
94 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 ...
1
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1answer
667 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 ...
25
votes
5answers
20k 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 ...
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1answer
2k 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
87 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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3answers
3k 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
617 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 ...
9
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1answer
2k 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? ...