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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how to check if mysql table is used or an application accesses the table in shell script?

A shell script is doing dump for a mysql table, but before dumping the table I want to check if this table is used by any other application. If so, I want to wait and enter in a loop until the ...
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60 views

Beginner question about bash “for loop”

When I do, for ((i=0; i<"${ARRAY}"; i+=2)) do echo $i echo ${ARRAY[$i]} done echo $i works as I expected, also echo ${ARRAY[0]} works, but with $i as iterator i see only blank lines. How ...
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21k views

Convenient way to check if system is using systemd or sysvinit in BASH? [duplicate]

I am defining common bash files which I want to use across different distributions. I need a way to check if system is using systemd or sysvinit (/etc/init.d/). I need this so I run appropriate ...
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794 views

Bash Scripting : Printing column data in the same row

I have written a bash script to calculate the size of a PostgreSQL database and print the output along with the date when the script was executed in a text file. The script code is as follows: ...
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2answers
155 views

Bash script : help file inside the script or in a different file?

I'm writing a script that has the vocation to be a fully featured program at the end. As far as I know, BASH is enough for his purpose (manage PPA's, kinda like Y-PPA). I would like to know how to ...
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1answer
80 views

Wait until no incoming network connection for N minutes, then execute a command

I want to put my Debian Wheezy home server to sleep, if it wasn't accessed through the network for a certain amount of time. I thought of a bash script that uses netstat to count the number of ...
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3answers
774 views

Delete files with same name at the end of the file

Delete files with same name at the end of the file i have a lot of files in my folder and sub directories like ajax_hostel_room_master.php.php class_hostel_registration.php.php ...
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1answer
2k views

Can Start Service With init.d script, however doing service <SERVICE_NAME> start does not work

I am running CentOS 6 and I am trying to get my Oracle database to run at startup. I have been following these steps: ...
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1answer
76 views

feeding the password without any terminal window (stdout)

I have a command like this: echo "12345" | sudo abcde where 12345 is supposed to be the root password and abcde a program or a command. I have a shortcut which runs this command. I have tested the ...
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2answers
305 views

When is it important to write portable scripts?

Most code I write is in PHP. I have recently started learning shell scripting. Most of the resources and tutorials that I've come across are specific to Bash. Some warn about bashisms and some don't. ...
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5answers
358 views

How can I force a script to use more resources?

I'm running a very time-consuming script which takes many hours to end. Watching top I see that it's only taking 5% of the CPU at best, usually around 3%. Is there any way to force the script to use ...
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450 views

A shell-like environment for binary processing

This question came to me a couple of times before, now in response to the question Loop through binary data chunks from stdin in Bash Answers given in ...
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1answer
51 views

How to run man with formatting in not interactive shell

I have webpage that process ANSI codes and output from man command (underline A as A\x08_) and I call php shell that execute bash -c "<command>" and print the output on the webpage. On the ...
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2answers
47 views

Help With Simple Script - Absolute, Relative Paths

I'm trying to execute a mono application, without requiring the user to type in 'mono filename'. It's just one line of code: mono ./Bin/jobshop.exe $1 $2 $3 $4 $5 $6 $7 $8 $9 It works great, so ...
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4answers
155 views

Wrapper command that runs program in temporary directory and deletes it after execution [duplicate]

I want to write a command that: takes another command as its arguments does a 'cd' to a temporary folder executes the command passed in the arguments removes the temporary folder afterwards ...
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1answer
106 views

How do I rename lots of files on a directory without changing their extensions? [duplicate]

I have a problem! I have a bunch of image files with extensions. Jpg and. Png. I wrote a script that renames the files, changing their names in a pattern followed by a number like this: ... ...
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3answers
182 views

creation of user add

I'm having more then 59 servers I need to create a script for user add. purpose: if I'm creating a user in one server it will be reflected on all 59 servers. How can I accomplish this?
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63 views

replacement script multiple targets

I have this input file Name=code_229633_138;isoforms=1 Name=code_229633_138 Name=code_229633_138;Target=R77_09738T0 Name=code_230519_1;isoforms=1 ...
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3answers
563 views

if/then/else man page

I would like to know if there is any man page documenting the construction of the most basic script commands like if/then/else, while, for each, and all the relative switches, like -eq, -e, -ge, and ...
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2k views

How can I extract/parse a complete URL from a semi random string?

I'd like to have bash parse/extract a full URL (and only the url) from a random short string. Examples: bob, the address is http://www.google.com or https://foo.com/category/example.html is up ...
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2answers
2k views

What's the most efficient way to grep for two completely separate things and assign the values to separate variables?

CentOS 6.x I want to take the output from curl, grep for two completely separate strings, and assign their respective values as variables. What is the most efficient way to do this (without writing ...
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2answers
877 views

How do I move all files output from a command?

I have this grep command to find files without the word Attachments in them. grep -L -- Attachments * I want to move all the files that are output from that command. How do I do that in bash? Do I ...
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208 views

Creating a shell script that parses and redirects number into next command?

I am trying to create a script that kills an Xorg process. Here is an example of me running the commands in a terminal: First, I find the process id of the Xorg program (in this case, 2494): . ...
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12k views

Check for Process if Same is Running

Is there a script or a way in linux that when I try to execute a shell script/process, if the same is running, it will prompt that same is running and will exit otherwise it will continue.
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118 views

grab multiple lines after a matching target line

This question is similar to How to show lines after each grep match until other specific match? thus answers may be similar to those there. I am trying to grab and extract from a file the lines that ...
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7k views

how to execute a python program in a shell script

I have a python program in that I wrote some python code (disk.py). I executed this program using the command python disk.py in a terminal, it worked. Now I want to execute it using a shell script.
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660 views

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
401 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
144 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
604 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
96 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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234 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. ...
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1answer
2k 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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462 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
114 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
63 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
132 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
2k 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
429 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
146 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 ...
2
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1answer
6k 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
398 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 ...
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1answer
95 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
12k 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
113 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
5k 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
768 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 ...
6
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1answer
132 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
184 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 ...