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

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1
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1answer
181 views

Silent installation of shell script using bash file [closed]

I have a setup file for Linux which is in shell script format. I'm trying to perform a silent installation by writing a bash script. When I directly access the script I'm unable to suppress the setup ...
3
votes
1answer
196 views

Approximating a floating point number with correct rounding off

How can I approximate a floating point number using shell-script (say, up to 4 digits after the decimal point)? I have two examples: A=1.2345678 and B=1.2345678E-05. So I would like to get ...
2
votes
6answers
4k views

Hiding Password in Shell Scripts

How can I hide a password in shell scripts? There are a number of scripts that are accessing database. If we open the script others also aware the username and password. So if anyone knows how to hide ...
0
votes
3answers
132 views

Creating a script that runs a simple command for all files in a directory

I need to use the text-based browser Lynx to dump 1000s of html files into text files, with the same filename. For any given filename.html the command is lynx filename.html --force-html --dump > ...
0
votes
1answer
111 views

Practical usage of “shift” shell builtin command?

I checked the /usr/bin/ssh-copy-id(part of openssh-client package at least under Debian) shell-script and it contains following if-statement: if [ "-i" = "$1" ]; then shift # check if we have 2 ...
0
votes
2answers
175 views

generate alphanumeric string from pattern

I want to generate host names for example from my patter like this: inc-[tnc][app|web][1-10] where it should output like below: inc-tapp1 inc-tapp2 . . inc-tapp10 inc-napp1 . . inc-capp10 inc-tweb1 . ...
1
vote
1answer
67 views

Can someone explain this tail + line to me?

I'm looking through some of the scripts that are on the servers and came across an 80MB shell script. Naturally curious I decided to look in there and came across this line: tail +4802 $0 | zcat - | ...
-2
votes
2answers
196 views

Enter a variable into a command in bash

My question should be simple for you guys. I am writing a simple script that runs a command but the file it would need is always different. Is there a way for it to ask: "Where is the file?" And ...
1
vote
3answers
91 views

How do I search for certain sections of a file and then extract only relevant information within that section?

I have a text file that is a server report which has about 1000 lines of information in it. I'm trying to write a script that can search the report for only certain pieces of information I'm looking ...
0
votes
1answer
38 views

Is it bad practice to put sections of main code in functions? [closed]

I didn't like the way the code that I had looked, so I compressed all of the main 'blocks' into functions. (This would also prevent the code from running if an error was present.) I don't know if this ...
10
votes
6answers
1k views

Is it possible to substitute “then” with brackets?

I first learned how to code in a C language, and using if ( code ) then code fi makes it really hard for me to read my code (don't ask why). Is there a substitute for then? Something like this: ...
-3
votes
2answers
49 views

Transform text records using only a “for” loop

I have an input file that is text, consisting of lines that look like: 352|C|PAID|7036|VOICE|01-FEB-12 I need to split each line into fields at the | (vertical bar) characters and output each field ...
-1
votes
2answers
44 views

OpenDNS automatic diagnostics

I've contacted OpenDNS support because advertising is not filtered on this site http://www.backpackerboard.co.nz/ They asked me to read these manual instructions OpenDNS Diagnostic Tool: What to ...
-1
votes
1answer
80 views

Comparing Oracle version in bash script

I'm trying to create a bash script to install an application that requires Oracle 11g client. How can I read in the version info within the bash script? sqlplus when run in Putty spits out the ...
0
votes
0answers
22 views

Run a command stored in a variable [duplicate]

I am working on updating some scripts we have used previously ( on RHEL) to work for a new flavor of Linux (ESX). As I am modifying the script, I wanted to add user feedback as well as some other ...
0
votes
1answer
719 views

How to clear log files periodically?

I am new to shell scripting. I want to clear log files in a directory based on the dates. I have managed to gather this code: DIR1='/home/u01/app/oracle/servers/DIR1/logs' ...
1
vote
2answers
139 views

How can I delete <93> <94> symbols in file? It is equivalent “ ”

I copied text from a PDF file in bash - vi and I get lines like this: echo <93>The Hypotenuse is $hypotenuse<94> I tried to change that in vi by: s/<93>/"/g But: E486: ...
4
votes
6answers
1k views

Loop in text files shell script

I have a list of files in one directory and a set of jpegs corresponding to each file in another directory. I need to loop over all files, and for each file name, determine the target directory. For ...
0
votes
1answer
63 views

A script to install OpenVPN & modify iptables?

I d like to automatize the install/config of OpenVPN on my client machines. Roughly, it should looks like : - apt-get openvpn - cp, edit, .... - modify iptables. Is it possible in one script ? or am ...
0
votes
1answer
48 views

How remove duplicates in same file and with if condition?

INPUT FILE: has all these values without header: customer ID, code, start_date, end_date 124343, DCW, 2015-07-06, 2016-08-03 235432, ABC, 2015-04-26, NULL 235432, ABC, ...
2
votes
4answers
149 views

How to see if there are any matching characters in a string?

I'm making a card hand generator, and I want it to note if a specific hand is generated, like a three of a kind or a full house. I was trying to figure out how to do it, and I thought of using grep on ...
0
votes
1answer
197 views

Creating service in SLES / SUSE 11 SP3

I have a python script that works very well executed from a (remote) console like this : sudo /srv/web-asset-server-master/python server.py The problem is, that it only lives as long as the console ...
-4
votes
3answers
270 views

find and replace strings with another string command line

I have a Ad-blocking hosts file with 0.0.0.0 IPs pointing to URLs. How to replace 0.0.0.0 with 127.0.0.1 command line without any visual text editor ? Manually doing this with nano , vi etc. is ...
0
votes
2answers
38 views

Where should startup scripts for a specific user be installed?

I have one script that will run when a specific user logs in. Where should this script and its assets be placed? I was planning to put it in /usr or /bin or /var, but I was wondering if there's a ...
0
votes
1answer
65 views

Terminal does not call 'then', reports a syntax error and command not found [closed]

I am a newbie for Linux. I have CentOS 7. I am running a very simple script from BASH. I executed the chmod command and then ran the script file from a terminal. I got an error saying "if command not ...
2
votes
3answers
100 views

Find strings in file1, count occurrences in file2

I have file1.txt with string values such as New Drug Application Drug Product Dosing instructions I need to count how often these strings occur in file2.txt with data such as Regulatory New Drug ...
1
vote
0answers
30 views

APCUPSD script can't close program

I want to use APCUPSD to stop a program (called ns_image_server) which runs in a terminal window when it detects that power has been lost, to give that program time to close before the computer shuts ...
1
vote
1answer
240 views

Passing multiple varibles to a script for SQL query

I have this script called info_code: #!/bin/ksh if [ $# -eq 0 ] ;then echo "Enter code : \c" read code echo "" else code=$1 fi code=`echo ${code} | tr '[a-z]' '[A-Z]'` echo "select * from ...
6
votes
5answers
135 views

How to find the next available file suffix (file_a.txt file_b.txt etc)

My system creates a new text file every time a certain event occurs. The files should be named file_a.txt file_b.txt file_c.txt etc. In a Bash shell script,how to find out what filename should be ...
0
votes
2answers
445 views

Using multiple awk commands within single line

Here is what am trying to do: My data is in sets of rows within same file (the variables vaa vbb are looping over it and am able to control it as required) What i need is to add an extra column before ...
1
vote
1answer
1k views

When to use #!/bin/ksh and #!/bin/sh? Need example [duplicate]

Also what are the main differences between these two. To execute a script is it necessary to write this at the beginning of script?
0
votes
3answers
1k views

In bash, how to call a variable and wrap quotes around its value as part of a command without causing the variable name to become a string literal?

So I want to add 10 seconds to a time. The command to do that came from here. To illustrate: STARTIME="$(date +"%T")" ENDTIME="$STARTIME today + 10 seconds" CALL="$(echo date -d $ENDTIME ...
1
vote
2answers
250 views

Using df and trying to awk a specific column

Among other problems with this script I am trying to make (this is the first unix/linux script I have ever made), I am trying to use df to get the % of disk space used and email it to the root. Our ...
3
votes
2answers
205 views

check for “errors” or “ORA-”

I want to check for "errors" or "ORA-" in Y.if there is an error then exit Y=`sqlplus -s user/passwd<< EOF exec test_Proc; exit; EOF` if [ echo $Y | awk '/ERROR/ || /ORA-/' ] ; then exit 1 fi ...
8
votes
2answers
501 views

Why does printf print more arguments than expected?

Why is this shell script printing inputs twice? I expected the script to ignore the inputs after 5. Script: #! /bin/bash echo "Enter 5 words : " read a b c d e printf "> %s %s %s %s %s <" ...
2
votes
3answers
255 views

Run a task in background and know the time of its termination

I need to run a unix shell script (my_script) in background and monitor it from web interface. I start the actual script from php like so: $command = 'my_script'; $pid= exec("nohup {$command} > ...
1
vote
2answers
116 views

Is it possible to have bash variables persist between runs

I am trying to create an init script which queries losetup -f for a free loop device. Within the init script I have a start() which queries losetup -f for the free loop device to setup some stuff, and ...
1
vote
1answer
58 views

Obtaining unique lines with matching strings [duplicate]

I have a JSON like text file of records with duplicate ids that look like: {"ID":"93" , "ST":[42,77,51]} {"ID":"21" , "ST":[43,4]} {"ID":"94" , "ST":[65,11,4]} {"ID":"93" , "ST":[42,77,51,29,63]} ...
1
vote
2answers
560 views

/bin/sh - echo >> operator not working as expected

I'm writing a shell script that appends binary contents to a file. I tried using this command: echo -en '\x61\x62\x63..' >> /tmp/myfile but that caused the following output: -en ...
2
votes
1answer
356 views

script running in crontab not giving output on shell screen

I am trying to run a simple echo script via crontab. I set that to run every minute, but it doesn't give output on shell screen. However, it runs fine when I run the script independently. Script ...
1
vote
0answers
572 views

sftp using socks proxy command with password authentication

I am struggling to make a sftp connection.We need to make a sftp connection to download files. My requirement is that we are moving from ftp gateway to axway and We were using ftp before to download a ...
0
votes
2answers
644 views

How to redirect unzip -v output to a log file in shell script [duplicate]

I have a script that loops through all zip files in a large directory and individually unzips them. I am using the -q option in order to keep the console clean and display other monitoring info. I ...
1
vote
1answer
112 views

Doing a 2>&1 redirection inside a script

Is it possible to run a script from within another script, and include a redirection into a log file? I'm attempting to run 3 scripts from within a larger script. One of them needs to be run "at ...
2
votes
3answers
1k views

What does “if $” mean in if $( ssh user@host “ [ -e file ] ” ); then …?

I saw script where the condition in an if statement used a $ and I don't understand why? if $( ssh user@host " test -e file " ); then echo "File is there" else echo "We don't that file on ...
2
votes
4answers
467 views

How to use and/or conditional in shell script

I have an if statement in a script. It looks like this: if [ "$a" != "0" -a "$b" != "100" ]; then #some commands here If I'm not mistaken, the line above will work if both conditions are true. ...
1
vote
2answers
372 views

CasperJS and PHP In Cron Job Cannot Open Files, Works Fine When Run Manualy

I recently got a new DigitalOcean LEMP environment with Ubuntu. I tried making an SH script that uses CasperJS to scrape data from an external website to a JSON file, and a PHP script to parse the ...
1
vote
1answer
158 views

Improving performance of script [closed]

I have been working on a script that can be used to automatically restart my Zabbix monitoring services in the event that they stop running. I have the script working just fine, but figured it could ...
1
vote
2answers
128 views

concatenating file names in a variable

I am attempting concatenate file names to use in a ftp mdelete command. Each file name needs to be separated by a space in order for the mdelete command to work. The $i variable is in a loop and I ...
2
votes
3answers
1k views

How to pipe output from cat to cut

I want to cat /proc/uptime into cut -f1 in a Bash script. I've tried; cat /proc/uptime | cut -f1 cat /proc/uptime > cut -f1 cut -f1 < cat /proc/uptime Do I need to use echo or something ...
1
vote
1answer
34 views

Why does this script give error?

Why does this script give error? #!/bin/bash # This script checks whether # the current user is root or # not. if [ $UID -ne 0 ] then echo "Non-root user." else echo "Root user." Fi ...