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

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0
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1answer
20 views

Write bash_history to a file with a timestamp

I need help with the script below. The requirement is to capture command line history in a file with specific date and time of commands, when they were executed. The below script captures history ...
0
votes
3answers
43 views

Extract numbers from a text file and place them in another file

I have a text file whose contents looks like this: ...
2
votes
0answers
23 views

How to read and do a min/max/avg from a NMEA stream

I have a weather station attached to my device spitting NMEA 0183 on /tty/USB0 I have alreeady sorted out how to parse the data and echo what I want in a script. What I need to do now is write the ...
2
votes
3answers
57 views

Sort files with a specific extension by modified time and store them into an array

I have found many answers to sort the files of directory and even to save them in an array. Sorting Example ls -t Directory listing in array array=(*) My particular problem needs to sort files ...
1
vote
4answers
47 views

optimize command with or and pipe to parse the output of ifconfig

I have this command line, but it's doubling the grep and awk ifconfig eth1 2> /dev/null | grep "inet " | awk '{gsub("addr:","",$2); print $2 }' || ifconfig eth0 2> /dev/null | grep "inet " | ...
0
votes
1answer
25 views

/bin/sh script error “arithmetic expression: expecting primary: ” + “ ”

ERROR: ./client-disconnect.sh: 22: ./client-disconnect.sh: arithmetic expression: expecting primary: " + " I just need to know how to fix it. It's for user accounting with OpenVPN. Script ...
1
vote
2answers
26 views

Script to Compare the “file size” with “last name of file” and if unmatched delete the file

In my environment, we'll be receiving files from clients into our Sftp. Sftp process the files, and move it to another tool, by appending the file size at the end of the file name. For example, ...
1
vote
2answers
47 views

Explain the shell command: shift $(($optind - 1))

I am not a Linux guy but stuck in some Script which I have to read for my Project. So can anyone can help me what this command is doing? shift $(($optind - 1))
1
vote
1answer
38 views

Pick columns from a variable length csv file

I have two CSV files, which share a column that is unique to each row in each file, like an ID. The files don't have a header. The file_2 has variable length columns e.g. 1,2,3 4,5,6,7,8 I joined ...
0
votes
1answer
30 views

How to execute R script attaching it to a shell script in Linux?

I am trying to submit a job to be executed on cluster. And this is done by writing an sbatch submission script. The job involves opening R 3.1.3 and running the referenced R script on the server. ...
7
votes
4answers
328 views

How can I make a script take multiple arguments?

This is a very simple script #!/usr/local/bin/bash set -e if [ "$#" -lt 1 ] then echo "Please insert at least one argument" exit else echo -e "\c" fi if [ -h "$1" ] then echo "$1 is a ...
0
votes
0answers
18 views

How can I use arptables to limit the number of outgoing ARP requests a second?

End goal: Make a script that will limit the number of outgoing ARP requests in a second using arptables. This is to have the ability to not trip the ARP-limiting feature on Cisco devices. I want to ...
1
vote
1answer
19 views

What's the Fedora equivalent of /var/lib/dpkg/info/[…].prerm?

Example file: /var/lib/dpkg/info/util-linux.prerm What's the Fedora equivalent of this file? (Not limited to util-linux - generic question for any package.) Use case: A prerm script is failing. ...
8
votes
1answer
333 views

Are [ “$VAR” = “” ] and [ -z “$VAR” ] always equivalent?

My code looks something like this: VAR="" while [ -z "$VAR" ]; do VAR=$( command | grep "important_string" ) done So I want to poll the output of command, until the important_string appears and ...
3
votes
2answers
6k views

Shell script throws a not found error when run from a sh file. But if entered manually the commands work

Im trying to use the following script to generate a sitemap for my website. When I run it as sh thsitemap.sh I get an error like this and creates an empty sitemap.xml file : thsitemap.sh: 22: ...
0
votes
4answers
89 views

The first Line of Scripting [duplicate]

what does #!/bin/bash at the 1st line mean ? Is it just a comment and ignored by the shell like all other comments in program OR Only this line is interpreted by the interpreter and all the other ...
10
votes
2answers
460 views

Differentiating between running and being sourced in a bash shell script?

Either what I'm asking here is extremely unorthodox/unconventional/risky, or my Google-fu skills just aren't up to snuff... In a bash shell script, is there any easy of way of telling if it is ...
2
votes
3answers
1k views

Query list of servers for memory/cpu allocated

Running RHEL 6.2, trying to write a bash script to SSH to a list of remote servers, and write the CPUs and Total Memory to a file, one line per host in the following format: HOSTNAME1 CPUS: 12 ...
9
votes
3answers
870 views

Is there a way to convert a zip to a tar without extracting it to the filesystem?

Is there a way to convert a zip archive to a tar archive without extracting to a temporary directory first? (and without writing my own implementation of tar or unzip)
1
vote
1answer
46 views

validate the sequence number in the trailer of a file

We have a file that arrives daily and has a sequence number in the trailer like 9999 TR SAP _AP Distribution 0000000000000001 where 0000000000000001 is the sequence number and the file that ...
-3
votes
0answers
25 views

Find the number of jobs present in each box. Find the number of child box in each parent box [on hold]

BOX_A--------------------SUCCESS JOB_AA--------------------SUCCESS JOB_AB--------------------SUCCESS JOB_AC--------------------FAILURE BOX_B--------------------FAILURE ...
4
votes
2answers
2k views

Negative arguments to head / tail

Variants of this question have certainly been asked several times in different places, but I am trying to remove the last M lines from a file without luck. The second most voted answer in this ...
-2
votes
0answers
18 views

script to check availability of mail server domain using wget command in solaris 10 [on hold]

#!/bin/sh /usr/sfw/bin/wget --secure-protocol=SSLv3 mail.google.com 2>&1 | awk '/^ /' if [ $? -ne 0 ] then echo "Server is UP" else echo "Error: URL "mail.google.com" is not ...
1
vote
1answer
122 views

How to use afl-fuzz (American Fuzzy Lop) with openssl

I am trying to use afl-fuzz with openssl in Ubuntu. A normal usage of afl-fuzz would be: afl-gcc test.c //-- this will produce a.out mkdir testcases echo "Test case here." > testcases/case1 ...
11
votes
10answers
8k views

Decoding URL encoding (percent encoding)

I want to decode URL encoding, is there any built-in tool for doing this or could anyone provide me with a sed code that will do this? I did search a bit through unix.stackexchange.com and on the ...
-1
votes
1answer
28 views

Starting Debian mono application (that has a GUI) AFTER boot is done [duplicate]

I've been trying to figure out how to start an application after Debian (Wheezy) is done booting up and on an LXDE desktop session. It is a mono C# application. The script I have is simply mono ...
1
vote
3answers
1k views

adding list of users to multiple groups

I have a shell script which add list of users which is listed in another file lets say users.txt. After that, I want my script to add users to multiple existing groups with condition, one user may ...
1
vote
1answer
43 views

Display a line in a text file if variable matches a part in the line?

I'm making a stock checker. I have a file with all of the NYSE exchanges and their descriptions. The descriptions start on the first tab enter of the file. The file formatting looks like this: A ...
2
votes
2answers
65 views

Difference of using () and $() to execute a series of commands

I am currently trying to make a script that creates bytes that will be piped as input to netcat. Here is the idea of the script: (perl -e "print \"$BYTES\x00\"; cat file; perl -e "print \"More ...
1
vote
1answer
679 views

How can I kill child processes with start-stop-daemon?

I'm writing a simple web server using nc and bash. It looks like this: #!/bin/bash rm -f /var/run/streamman/out mkfifo /var/run/streamman/out trap "rm -f /var/run/streamman/out" EXIT while true do ...
1
vote
1answer
38 views

Find last line of a file for matching string?

I want a loop that runs infinitely over a file but always checks the last line to see if it contains the matching string if it does then echo that line and keep the loop running. What I have right now ...
-4
votes
0answers
14 views

Shell Script to Generate Automatic ticket/Email [on hold]

I have a requirement to generate an auto ticket/email when it's time for a scheduled task to be done and it should repeat again when it's time for performing the task. Could you please help me with ...
0
votes
1answer
23 views

Want to use find with rsync in script

I'm trying to make a script that will run in cron, that will search a path for specific file name. In the path there might be more folders with that same file name. If found and they are newer than 2 ...
-2
votes
2answers
45 views

How to make a password box in linux? [on hold]

I have a script but can't find mistake: #!/bin/bash data=$(tempfile 2>/dev/null) trap "rm -f $data" 0 1 2 5 15 dialog --title "Password" \ --clear \ --passwordbox "Enter your password" 10 30 ...
6
votes
7answers
4k views

How to create a testcolor.sh like the following screenshot?

I found this image on the internet, but don't know how was it made, Can anyone provide a sample on that? I just would like to have a color table as well.
3
votes
3answers
92 views

How to kill this process in bash

I am trying to interface my homemade Raspberry Pi-powered arcade machine with a coin acceptor, and for that I: use a shell script (named gameplay) which starts the game emulator (MAME) when a coin ...
1
vote
2answers
29 views

How do I generate diffs for a series of files?

I have a series of a few thousand files, all with filenames in order, so let's say file1.x, file2.x, file3.x, etc. All these files are in the same directory. I know how to generate a diff from ...
3
votes
2answers
124 views

To count number of matches in a mega string quickly

I have big text-data without spaces and without other rows in one line. In reality, the streams are 0.2 Gb/s, similar situation here, but in this task, counting occurrences which is more challenging ...
4
votes
1answer
167 views

string in a file as a variable

I have a conf file content like below. file.conf: key="name" value="pswd" Now I want write a script to having two variable like above script.sh key="name" #key as variable value="pswd" ...
5
votes
1answer
96 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 ...
-1
votes
2answers
44 views

shell script not running using crontab

This is my script mboxutil -l > n.txt sed 's/^.*user//' n.txt > n1.txt cat n1.txt | sed 's/^.//' > n2.txt sed 's/\/.*//' n2.txt > dss_list.txt rm -f n.txt rm -f n1.txt rm -f n2.txt sed ...
1
vote
3answers
46 views

Killing the previous instances of a script before running the same unix script

I want to kill the background process of the same shell script that i am going to run again. That means before executing the shell script i want to delete the background process running for the same. ...
2
votes
1answer
42 views

Stable timing for shell scripts?

The run times of scripts vary quite much. I would like to find similar time -function as Matlab's timeit, described here. For instance, I am evaluating these commands here about counting quickly ...
1
vote
2answers
26 views

bash command/script to reset default route

I manage several OpenWrt (embedded linux) routers for which I've written bash scripts to run an Openconnect VPN client. The client uses "vpnc-script" to set up routing, which replaces the initial ...
1
vote
1answer
20 views

Conditional file and directory installation in Debian Packages

Is it possible to create a binary Debian package with conditional files and directories installation (e.g. installation of an init script in /etc/init.d/ after being confirmed by user)?
0
votes
1answer
20 views

How to make sure the same string doesn't appear next to itself in an array?

I'm making a Rubik's Cube scramble generator, and the turns can't be side by side or else it's useless. I'm trying to stop it from doing the following: Displaying the same string twice, i.e R2 R2 ...
0
votes
2answers
43 views

expect: does “” (spawn_id exp70) match glob pattern

I have written an expect script that works perfect for testing passwords on our network until it has looped through my list quite a bit, then the debug output shows that there is nothing to match. ...
1
vote
2answers
714 views

Command/scripts to check the Reverse DNS Lookup time

I am working on a project in which one master communicates with numbers of slaves. For that it has to make connection with hosts in network. But sometimes it hangs. I think that the reason behind is ...
3
votes
2answers
63 views

Script for changing modification time of files and directories recursively

I have many big folders with thousands of files in them and I want to use touchto set their modification times to be "original time"+3 hours. I got this script from a similar thread in superuser: ...
1
vote
0answers
34 views

This code isn't working. (Trying to declare array values in a for loop and do math functions on them)

I was again bored and looked up a list of programs to make in bash, and I'm trying to make a CC (credit card) validator. I had to split the characters into an array to do the validation, and I think I ...