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

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Modification needs to be done in iptables in case of a bridge between two interfaces is implemented

I have a machine with 2 NICs; eth1 and eth2. Each NIC has an assigned IP address and the traffic between them is controlled using the below script. #!/bin/bash SAT_RECV="192.168.200.0/16" NQ=9 ...
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2answers
23 views

CRON Job To Execute Command On Low Memory

I have a situation where I may need to execute an SAP command line tool hdbsql when memory gets too low (to help clean out the HANA table cache). I'm not well versed in Unix/Linux, and was wondering ...
2
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2answers
112 views

bash: can't set a variable to a solid string [duplicate]

I cannot set a variable with a whole command-string as following: A="/bin/ps wwwaux" for a in $A do echo "$a" done It assigns array instead of solid string somewhy. Could you assist, please. My ...
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0answers
38 views

How to turn Diff command into bash script with prompt

I have a list that i've copy and i want to paste it to the shell to give me just the repeated lines. 1 1 3 2 As i read about bash commands i've maded this: cat > /tmp/sortme ...
2
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1answer
109 views

Task not run by crontab

crontab strangely does not execute my script, although the script is running just fine from the shell terminal. I already made sure that scripts are separated from each other by a new line space. ...
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2answers
35 views

Alignment when printing a series of records

How can I resolve the problem of the tables going to the right. I just want it to be shown under 1. Here's my script with START added. The alignment has gone wonky now: while IFS="," read f1 f2 f3 ...
7
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1answer
203 views

Know which process does I/O without iotop

On Linux, I want to know which process uses my disk I/O bandwith. I know I can use iotop but I have a machine where, for various reasons, iotop cannot be installed. How can I manually get that ...
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0answers
31 views

awk search for string containing forward slash in variable [duplicate]

I'm searching for a string in a massive XML file. Snip: <sv:node sv:name="notfound"> <sv:property sv:name="jcr:primaryType" sv:type="Name"> ...
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2answers
33 views

sed replace after matching character

I have to change a properties file containing the property: ro.product.firmware=0.0.1 with a new value that is coming from a function called in a different section of my bash script. I cannot get ...
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3answers
118 views

Script to check if file exists and copy

Pretty new to shell script, want to write script which checks if any file .300 extension exists on /exports/files on server 10.xx.xx.xx. If *.300 exists, move file to /exports/files/arch and send an ...
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1answer
29 views

How to duplicate lines in a text (xpm) file?

I'm having some pixmaps like this (36, to be exact): /* XPM */ static char * hide_active_xpm[] = { "12 14 3 1", " c None", ". c #EDEDED s active_color_2", "+ c #313739 s active_text_color_2", " ...
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3answers
71 views

How can I count the number of times a phrase appears in a file, and format it neatly?

I have a log file I am trying to pull data from. It is formatted like so, and lists when certain modules are checked in and out: 19:50:26 (license_manager) OUT: "certain_module" doej@server.domain ...
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1answer
30 views

Why does bash try to execute strings in a string substitution?

My script is supposed to take input from a pipe and replace newline characters with commas, using the bash's string substitution: #! /bin/bash read -d -r input echo $input $input=${input//\n/,} ...
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3answers
55 views

Find the complement set of an array?

Following from this question, where I wish to extract 10 random lines from a file, I now wish to also have the remaining 90 lines as a separate file. Since the document has 100 lines, indexing from 1 ...
1
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2answers
39 views

Re-print an array in a certain format?

I wish to take 10 random lines of file, which is 100 lines long. First, I randomly generate 10 integers between 1 and 100 (inclusive) with ind=$(shuf -i 1-100 -n 10 | sort -n) Then, I wish to use ...
2
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3answers
53 views

Specific column level substitution

If I have a file with columnar entries, is it possible to substitute specific entries from a specific columns only and save changes to the same file?? Example a file abc.txt: SR|FRUITS|COLOR| ...
1
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2answers
41 views

Substrings in shell script

Am trying to get a substring from a string but am getting the error: ${curr_rec:3:4}: bad substitution #!/bin/ksh get_file_totals() { if [ -e "$file_name" ] then IFS='' ...
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1answer
45 views

In ShellScript, how to call a function after completion of function which is already running?

My script involves three shell functions. Two running in parallel. I have to call a third function when the two parallel running function completes it's execution. How to call that third function? ...
2
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1answer
46 views

POSIX shell scripting and performance tuning [on hold]

Nowadays, I'm researching for performance tuning for shell scripting , And I have been prevented to POSIX shell scripting, However it's only a standard, But I think it's rathar than standard for do ...
4
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1answer
40 views

Settings environment variables from a file

I want to have a file (outside of git) that contains certain environment variables. While a script (which is in git) needs to read them and export to env. My current implementation works for ...
3
votes
1answer
43 views

BASH: Fifo troubles - seems selective about input

So I am having a problem with a BASH service in Debian 7 that I've been working on for quite a while and that randomly started having trouble with its fifo, or so it seems. It is based on kind of your ...
2
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1answer
34 views

How to detect if DE is Unity or XFCE via shell script?

I have a few configuration scripts that I run everytime I install a fresh version of Ubuntu. Recently, however, I migrated to Xubuntu. I would like to use the same script for both distros, since both ...
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4answers
325 views

How to atomically allocate a loop device?

I am writing some shell scripts to handle some disk image stuff, and I need to use loop devices to access some disk images. However, I am not sure how to properly allocate a loop device without ...
4
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6answers
141 views

Append something to each list in a file

I have a file, lists.txt, that looks like this: // stuff at beginning of file var list1 = new Array(); i = 0; list1[i++] = 'a'; list1[i++] = 'b'; ... list1[i++] = 'z'; var list2 = new Array(); i = ...
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5answers
40 views

Output to variable with an indirect command (eval)

What is wrong with this indirect command when run with eval ? #!/bin/bash OS=AIX host=myhost CMD_AIX="(o=\`host \"$host\" \`)" CMD=\$CMD_$OS echo $CMD eval echo $CMD eval "$CMD" Ouput: $ ...
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4answers
101 views

Script to log temperature

I have been trying to write a BASH script to log my raspberry pi's temperature. My plan is to run it as a crontab every 15 mins or something. However I keep getting errors, I think it's something to ...
4
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3answers
247 views

How to use printf and %s when there are color codes?

I had these lines: if [[ $# -eq 0 ]]; then printf "$fail_color Error - Function: $function, Line: $line_number \n" printf "do_test: Third parameter missing - expected result\n" exit 1 fi This ...
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3answers
46 views

Find a file with the extension .csv in a directory matching a pattern

I have a folder in which I have many subfolders. The Root folder name is allCSV and sub foldername is will be like a_date(s), b_date(s), c_date(s) ... I want a file which is in a_date(s) and ends ...
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1answer
33 views

cant run dd command on android device

The main objective is to send a splited file to an android and join it back up with a .sh script, the file is splited to 5MB parts but its total size is unknown (trying to make an universal script), ...
5
votes
3answers
195 views

Easiest way to find missing quote in a bash a script?

I have a bash script which is currently 700+ lines long. After a particularly long round of editing, it now errors like so: ./run_me.sh: line 693: unexpected EOF while looking for matching `'' ...
4
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4answers
142 views

Move files by date into different directory using CLI

I have a large number of pictures from an old hard drive that I'm trying to organize. If I run ls -l, I notice all of these files have a creation date of 2012 or before. Ideally, I'd like to move ...
2
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1answer
54 views

Checking if a specific key is pressed in shell script

Is there a way I can check if a specific key is pressed in a shell script which is running in background. Consider I am running a shell script which has to play a play list of songs as soon as I press ...
2
votes
4answers
80 views

Extract two values from the output of a command

I'm using the following command in a script to get synthetic wifi info: echo "$( iw dev wlp1s0 link | grep '^\s*SSID:\s' | sed -r 's/^\s*SSID:\s//' ) $( iw dev wlp1s0 link | grep ...
1
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1answer
69 views

Which one works faster - regular operators (such as <,>,=) or using (-lt, -gt, -eq)? and why?

Which one works faster - regular operators (such as <,>,=) or using (-lt, -gt, -eq)? and why?
2
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3answers
47 views

How can I prepend and append to each member of an array?

I have an array: CATEGORIES=(one two three four) I can prepend to each array member using parameter expansion: echo ${CATEGORIES[@]/#/foo } I can append to each array member the same way: echo ...
0
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1answer
41 views

Test variable in a bash case statement

What I want is simply to do something if the first variable of the script is empty, in a case statement. Unfortunately I spent yet a certain amount of time searching for the solution but didn't find ...
0
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2answers
29 views

Timeout function return value

I'm using the timeout function on debian to wait 5 seconds for my script. Works great but the problem I have is that I need a return value. Like 1 for timeout and 0 for no timeout How am I going to ...
4
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0answers
50 views

Bash Script — ffmpeg not being invoked as expected

I'm working on a bash script to convert my music library to ogg* but executing the right command is somehow eluding me. This is the line that should accomplish it: ffmpeg -i "${file}" -f flac pipe:1 ...
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0answers
16 views

Why “killproc” command is unable to terminate a script(whiled loop with inter sleep)? [closed]

How to terminate a whiled loop script using "killproc" without using script's pid?
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1answer
27 views

PHP script to monitor process and write status to a file

I want to write a php script for monitoring particular process using top command and write into the file. I use top -p pid for monitoring a particular process and also i write a shell script for ...
3
votes
4answers
47 views

How to get the PID of a sub process across to the parent process in a bash shell script?

My shell script is as following: #!/bin/bash ./process1 #It will create a sub process: sub_process1 while [ condition ]; do break done kill -9 process1 and sub_process1 In my script, it will ...
19
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5answers
1k views

How can I propagate my SSH pub key to a list of servers without having to type my password in over and over?

I was recently given username/password access to a list of servers and want to propagate my SSH public key to these servers, so that I can login more easily. So that it's clear: There is not any ...
1
vote
1answer
19 views

Script samba password but securely

I want to script the addition on a samba user and the password. I have seen solutions similar to the one here Piping password to smbpasswd echo -ne "$PASS\n$PASS\n" | smbpasswd -a -s $LOGIN but ...
1
vote
2answers
34 views

Url Decoding shell script

How can I store the url-decoded string in a variable using shell script #!/bin/sh alias urldecode='python -c "import sys, urllib as ul;print ul.unquote_plus(sys.argv[1])"' ...
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1answer
20 views

Help killing off Process for Mem Leak

I am currently building an Android LP kernel, and have some pretty sweet tweaks already running and built into it. I know there are numerous LP memory leaks (i've already got the bootanimation one ...
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1answer
32 views

Webpage content - search for pattern & save to file

I have a web page, say https://test.salesforce.com. I would like to search for a pattern, e.g. "src" at the beginning of a line in the entire webpage content. If the pattern is found, I need to ...
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0answers
25 views

Run Loop between starttime and endtime and get data from url

I want to check two conduction and run a loop for every one minute. There should be three variable start_time, end_time and current_time Conduction's: start_time should be greater than ...
2
votes
1answer
43 views

How do I properly escape this long su + sed command?

#!/bin/bash wineuser=tom su $wineuser -c "sed -i '$ialias ptgui "wine ~/.wine/drive_c/Program\ Files/PTGui/PTGui.exe\"' /usr/people/$wineuser/config/cshrc.csh" The acutal line inserted to tom's ...
14
votes
3answers
388 views

Prepare answers for questions of a command

Let's say I want to write a shell script that executes just one command. But this command is poorly designed. It doesn't offer any command line options; instead it asks some questions and waits for ...
1
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0answers
42 views

Shell Script to change user shell

I am writing a script that would be invoked to change user shell. The basic requirement is that once user gets authenticated (e.g: thorough some web application) the script would be invoked to set the ...