Questions about shell scripts, executable files that are interpreted by a shell (bash, zsh, etc.).

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2
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1answer
1k views

What's the problem with this script to change wallpaper?

I'm very new to Linux's world, so I would ask to forgive me for every stupid or too simple thing I will ask now. I installed Elementary OS from their website just yesterday. I wanted to change my ...
2
votes
1answer
158 views

Why does backslash get converted to space in echo statement if IFS='\'?

Why is \ is converted to space on setting IFS='\' var="'(]\\{}\$\"" IFS='\' echo $var # '(] {}$"
2
votes
1answer
161 views

Regular Expressions within a string in AWK using if/then control structure?

PROBLEM I want to specifically use AWK (GAWK, MAWK, whatever) in an AWK script to sum up the values in field 9 for every record that contains "runner__.jpx" (the underscores are placeholders for two ...
2
votes
1answer
1k views

Send attachment to gmail id from shell script

I have a shell script that generates reports. Using crontab i run the scrip everyday at 1000 hrs. I want to mail that report to my gmail id as an attachment. I have tried using mutt but it doesnt ...
2
votes
4answers
3k views

SSH exits after quit case in bash script

So I have the following standard script: #!/bin/bash PS3='Please enter your choice: ' options=("option 1" "Option 2" "Option 3" "Quit") select opt in "${options[@]}" do ...
2
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4answers
11k views

Shell script to check for the presence of one or more files with a specific extension?

I want to write a script to find a file with specific extension.this much i have done: #!/bin/bash file="/home/Savio/Dsktop/check/*.csv" file1="/home/Savio/check/*.txt" if [[ -f "$file" && -f ...
2
votes
1answer
93 views

Pipeline each line of a file to a specific variable in a second command

I want to execute the following instruction: basex -bword=ENTRY consulta.xq But for every line of a SampleText file (plain text mainly). The SampleText contains the following lines: hello evening ...
2
votes
1answer
934 views

Bash nested command substitution not working

Hi I have a bash script that intend to run via watch ./script.sh It's to debug a cooling problem with my laptop, however the script I wrote isn't working as intended. I'm quite new to bash scripting ...
2
votes
2answers
283 views

Is tty_nr referenced anywhere else in GNU/Linux procfs?

This is a problem I've been trying to solve on my own for some time without any luck. I'm trying to write a script that (amongst other things) can take an arbitrary PID and map it to TTY device's path ...
2
votes
1answer
252 views

Is there a text-only equivalent (no curses) of `zenity --question`?

For my mercurial commit hook, I want to run my test cases and be asked whether I really want to commit if any of the tests fail. I'm thinking something like <run-the-tests> || ...
2
votes
1answer
421 views

Prompt user for sentence and store it without being disturbed by spaces

I have a bash function that prompts user to input certain data. I tried it with first name, last name, birthday etc. Data that is mostly represented in one sentence. When I ask for street + no. the ...
2
votes
1answer
1k views

How to check if a currently running process is opened by root or user

I'm currently creating a BASH script to kill off processes. I first check if the process is running then kill it. But I would like to add a nested if to find out if that process was opened by root ...
2
votes
3answers
1k views

Very strange behavior with grep and IFS

I'm having trouble using grep, the returned results are "n-empty", I mean without the 'n' character... This is the script sample : OLDIFS=$IFS IFS="\\n" i=$(grep -ril $1 *) echo $i IFS=$OLDIFS ...
2
votes
1answer
111 views

Deleting a pattern from a file and appending it to the end?

I have a log file which have contents like below: #SOME MORE DATA These switches don't have latest images : SWEs-elmPCI-A-01# #SOME MORE DATA These switches don't have latest images : ...
2
votes
2answers
747 views

Ubuntu Bash - Changing permissions to user files for automating Apache VirtualHost creation

Moved here from AskUbuntu I currently have a small Ubuntu Server 12.04 machine (test environment) with about 3 non-root users created. Each user has their own public_html directory under their ...
2
votes
2answers
577 views

add “#” in begining to selected lines in File

Requirement : ADD someting (i.e #) in begining of every line in file A which is grep from file B File A abcd abdc sdfg asdfa jon ram File B jon abcd grep file B from file A and add "#" ...
2
votes
1answer
1k views

How to create a password protected shell script [duplicate]

How can I create a password-protected shell script for read/write access. It should also be executable by all users without the password. I have sensitive information in the script.
2
votes
1answer
97 views

How do I change the colour of all lines to red begining with a % symbol?

When I use sed -i "s,.*%.*,$(tput setaf 1)&$(tput sgr0),g" A.log the whole line vanishes and when I use sed -i "s,^%.*,$(tput setaf 1)&$(tput sgr0),g" A.log only the first character(%) ...
2
votes
1answer
542 views

how do i suppress seds unnessary output while using option -e?

why n option is not working here [root@testgfs2 final]# echo a b c | sed -ne 's/[[:blank:]]/"/gp' -ne 's/^/"/pg' -ne 's/$/"/pg' a"b"c "a"b"c "a"b"c" i just need : "a"b"c" actually ...
2
votes
1answer
854 views

How to wait for a subprocess used for I/O redirection?

Consider the following snippet of Bash script: exec 3> >(sleep 1; echo "$BASHPID: here") do-something-interesting exec 3>&- wait $! echo "$BASHPID: there" When executed, it produces: ...
2
votes
2answers
4k views

how to move (not copy) files from one server to another?

I want to move files from server1 to server2. A producer on server1 will keep generating the files, and a consumer on server2 will keep processing them. I can copy files using the following shell ...
2
votes
1answer
3k views

Bash variable in Awk script

I have this flat file database(ff_servers.db) with following contents: 192.168.154.2 Alaska hp 192.168.157.3 Colorado dell 192.168.156.3 hawaii hp From command line, I could run: awk ...
2
votes
1answer
83 views

Listing script's file dependencies

Given a shell script, is there an easy way to extract what files it manipulates explicitly (so not like concatenating some command and than eval-ing it)? E.g. #!/bin/bash . /etc/someconfig.cfg ...
2
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2answers
224 views

Does a parent bash script remember the cd history from a child bash script?

Example: mainscript.sh cd /mnt/something ./buildscripts/000-script.sh 000-script.sh cd /mnt/otherthing mkdir something exit
2
votes
1answer
2k views

Inserting a file into another file using sed

I want to insert the contents of file1 into file2 after a matching PATTERN. I want to do it only after the first occurrence of the PATTERN. I would like to know the modification I need to make to ...
2
votes
1answer
795 views

Parsing SQLite output

Using -line Option I get this output from SQLite: row1_column1 = valueA row1_column2 = valueB row2_column1 = valueC row2_column2 = valueD So one line for each column value and result rows are ...
2
votes
3answers
1k views

Timeout `idql` command in ksh

I probably read all the threads in almost all the forums for a solution to my need. I am a beginner in shell scripting and I dont have a perfect solution yet. Below is my code snippet. idql -n ...
2
votes
2answers
1k views

How to merge chunks of text files in a directory to one or more files?

I have a requirement to merge chunks of text files in a directory to one or more files and then zip the merged file. For ex: If i have half a million text files in a directory, say A. I want to merge ...
2
votes
1answer
2k views

How to format a curl command for a special task?

There is a search page in a form http://site.com/search.php and it sends a search query via POST request. I want to fetch this request via curl command line tool to inspect a POST request. The HTML ...
2
votes
1answer
1k views

How to script a database migration using SSH?

I am trying to create a sync.sh script that coordinates with our less-than-ideal version control for our website. This script will migrate a copy of the live database to our local development ...
2
votes
3answers
6k views

Faster awk script to get the substring / string we wanted

ORDER EVENT .........[] [] ... so many other tags... [Account<25106>=ACCT1] [Destination...] .. so many other tags. I am currently trying to get the account like this. I tried using match in ...
2
votes
2answers
476 views

Why does “$i | sed” not work?

I have this code: if [ $i | sed -e "s/^.*\(.\)$/\1/" = "/" ] then echo "folder" else echo "file" fi where $i is something like this app4/ The code above should get the last char of the ...
2
votes
1answer
3k views

Script to SCP files works manually but not through cron

I'm using CentOS 5.6. The below code might have some typos as I needed to change real info to fake info for security reasons: backup.sh #!/bin/bash set -vx rm -v /server/temp_db.gz rm -v ...
2
votes
5answers
938 views

How to find out if PWD contains spaces or non-English letters?

I created an environment variable: WD=`pwd` How can I check if it contains spaces or non-English letters?
2
votes
1answer
1k views

How synchronize two disks (or folders) using symbolic (or hard) links (like rsync)?

I'm searching a tool or a shell script or another program to synchronize two or more folders or disks. But it differs of rsync tool, because, I don't want to duplicate the missing file, but do a ...
2
votes
2answers
368 views

List files that occur lexically after/greater than a given prefix (or, run database upgrade scripts in a proper order)

I'm trying to create a shell script that runs through a bunch of SQL scripts. I've these files: $ ls upgrade/ 01-foo.sql 02-bar.sql 02-baz.sql 03-foo1.sql 04-buz.sql And I've got the version of ...
2
votes
3answers
886 views

regexp in ksh for extensions tgz, tar.tgz

I'm trying to get a regexp (in ksh) to identify files with only the following extensions: tgz, tar.gz, TGZ and TAR.GZ. I tried several but can't get them to work. I'm using this regexp to select only ...
2
votes
1answer
465 views

How to install a database dump via Shell Script?

I have a Mysql database dump. I want to install it with Hudson via a Shell Script to an external Linux machine. How can you take a Mysql script and run it inside a database on other machine? I know I ...
2
votes
1answer
311 views

What's wrong with my bash script?

I am trying to utilize zenity in my simple ffmpeg-cut-mp3 script, but it hangs after the input into zenity :/ What's the matter with this? #! /bin/bash start=$(zenity --entry --title="CutMp3" ...
2
votes
1answer
6k views

How to run sh from sh file

I developed a Java application. I divided the application into 5 sub-applications, and created a service wrapper to each sub application using shell scripts: subaap1/bin/app.sh subaap2/bin/app.sh ... ...
2
votes
2answers
54 views

search contents of files that are packed in a zip file

For my school project i have to create a script that allows you to search the contents of files that are packed in a zip file. You can give a "search string" with the script, followed by one or more ...
2
votes
1answer
28 views

( test -n $st ) != ( test -z $st ) right?

As I read, test -n $string ==> Exit status is 0 if $string is not null, 1 otherwise and test -z $string ==> Exit status is 0 if $string is null, 1 otherwise But in this particular example, (I ...
2
votes
3answers
84 views

Replace values in file

I have a files: $cat file1.txt 1234|W 1345|S 8427|D 2132|C 3243|V and my sql file is : $cat select.sql SELECT * FROM CUSTOMERS WHERE ID IN (FLAG); and I have a shell with the next ...
2
votes
1answer
28 views

Bash shell script program that prompts for and reads two integers from the user.

Okay, so I been trying to figure this problem for a while and I'm coming up with errors left and right. This is my first time trying to learn the basics. So any advice would be helpful! Problem: I'm ...
2
votes
2answers
67 views

bash read of a newline, printf reports character 0

I use bash printf function to print ASCII codes of characters in an input file, but for some reason printf outputs ascii code 0 for LF characters, instead of 10. Any ideas why? while IFS= read -r -n1 ...
2
votes
2answers
41 views

Using awk to combine two csv files on three fields too create a new csv file

I would like to compare fields in 2 csv file and create new csv file for output. I have 2 csv files; this first file is PCs in my network: ...
2
votes
2answers
40 views

What's the difference between 'test' and evaluating with /dev/null?

I noticed different .sh scripts for homebrew which check whether it's installed. One uses this syntax: if test ! $(which brew); then The other uses this syntax: if ! which brew > /dev/null; ...
2
votes
1answer
25 views

Connect via telnet and doing certain operations

I'm trying to code a script where I can connect via telnet to another server and execute certain operations, but I'm having problems with the result of this process. The objective is to connect to a ...
2
votes
1answer
40 views

Bash script to summarize “ last -a ”

I would like to make a shell script such that it runs the " last -a " command and summarizes it's data in the form : userID : number of login sessions Host or ip1 - number of ...
2
votes
2answers
60 views

Updating shell functions and aliases through environment variables

Say we define the following shell function and alias in .zshenv: export VARIABLE_A='original' function my_function() { print $VARIABLE_A } export VARIABLE_B='original' alias my_alias="print ...