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

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326 views

remove lines where a field's value is less than or equal to 3 - sed or awk?

I need to remove every line that has a value of 2 or less in the 8th field (column). My data looks like this: 12-31 Airport 189 379 41 49.70946503 -124.91377258 2 2880 30.8 01-01 ...
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35 views

Record commands only to file

How can I record commands only to a file? I imagine something like the script command, but not recording prompts or the OS response, just the entered commands followed by a line feed. I want to ...
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193 views

use “read” command to pass lines as positional parameters to a shell script

The following file runs, but not doing anything, yet it does not error.... while read dates; do ./avg_hrly_all_final.sh ${dates}; done < ./dates_all.csv I have a list of dates in ...
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2answers
139 views

Extracting numbers with a decimal point from ls output in Bash

I would like to extract the numeric part of the file names that begin with "hsli" and end with ".h5" in Bash on Ubuntu 14.04.1 64-bit LTS. My ls -l hsli* output is as follows: -rwxrwxrwx 1 ongun ...
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180 views

print the output of 2 commands in 1 file on the same line

Thanks for looking at this. I have a possible simple question, but I wasn't able to find any help so far on the internet. I have a script that has mainly 2 commands that process output. But both ...
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82 views

Is there any way to make scripts dynamic? [closed]

I need my script to show the time till next run, continuously like a timer, is this possible?
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190 views

How do I automate opening Firefox over an ssh tunnel?

My university has access to some academic journals that I cannot access from home. To be able to download papers while I am away, my current proccess is: Create an ssh tunnel to my university ...
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1answer
257 views

How can subtract 2 floats which have been extracted from 2 other files with BASH [duplicate]

I'm trying to get the difference between two numbers which I have taken from two files. I think my code will make sense: I've tried to make it work by two different methods, didn't work. What I get ...
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5answers
300 views

Comparing float values in bash

My if expression always evaluates to TRUE somehow. ROTATION variable is 0.000 or 90.000, a float value or it seems so ROTATION="$(mediainfo --Inform="Video;%Rotation%" $VIDEO$ORIGINALEXTENTION)" echo ...
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234 views

Cronjob doesn't execute shell script, but when I am executing it standalone it works. Why?

Shell Type: >echo $SHELL /bin/ksh Cronjob : 15 * * * * /bin/ksh /wls_domains/resMGT/logs/bea/wlr3queuetransaction.sh > /wls_domains/resMGT/logs/bea/data/script.log The script is as below: ...
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380 views

Compare two Arrays in KSH and output the difference

I am not extremely familiar with KSH (Actually just started using it) and I am having problems with trying to create a script that will essentially compare two arrays that have been stored and then ...
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627 views

Sort files according to their extensions

I have made a script that will sort files according to their extension and place them in the proper folder. For example, place abc.jpg in the directory jpg. #!/bin/bash #this script sorts files ...
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2answers
56 views

disk space by individual user

I have around 50 user folder under etc/main/ folder. Now i want to get 10 large space user folder detail. Note: I don't want sub-folder of each user..I am using Ksh script. Example: /etc/main$ ...
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2answers
157 views

syntax error in conditional expression

I am writing a script where I am using the combination of logical 'OR' and logical 'AND' statement. This is the script: #!/bin/bash echo "Enter the value of a" read $a echo "Enter the value of b" ...
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4answers
96 views

How to use regex in sed?

I need to revoke the sudo access to the user using sed in scripts. I want to comment the user only if the line contains /bin/su - root Let us consider the file as below, in which I have to comment ...
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1answer
341 views

Find the process which is taking maximum CPU usage if CPU usage is more than 60%?

I am trying to measure the cpu usage of my ubuntu machine and if the cpu usage is more than 60%, then I need to find out the process who has the highest cpu usage and then send out an email saying CPU ...
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2answers
222 views

A tiny and simple script fail and this is the output “No such file or directory”

The script is: #!/bin/bash IFS=" " command="ls /tmp" for file in `$command`; do echo $file done And the output is: $ ./test.sh ./test.sh: line 17: ls /tmp: No such file or directory
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3answers
218 views

Input two numbers and add them when “a” is typed, subtract when “s” is typed

So I'm having a little trouble with this code. When i try to execute I get the message line 12: 0: command not found #!/bin/bash let results=0; echo "First number please" read num1 echo ...
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2answers
333 views

Extract text from one iteration of top

I want to execute the top command from my bash script the problem is that usually when I type the top command on the console , I exit by Ctrl+C. but how to exit from top when I run the top command ...
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2answers
548 views

Pass parameter from one shell script to another

I have two shell scripts namely test1.sh and test2.sh I have to call test2.sh from test1.sh For test1.sh I need to pass one parameter as a command line argument and for test2.sh I need to pass a ...
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398 views

make `find` return with a non-zero exit code if error occured

Why am I seeing the following: $ find -not -exec bash -c 'foo' \; -quit bash: foo: command not found $ echo $? 0 This is a reduced version of the actual script I am using which I post at the end ...
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132 views

How could i flip content of a binary file with bash commands

I was wondering if it's possible to do bitwise conversion on a binary file, with bash commands, (in my case bitwise negation).
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198 views

How can I get the pid of a process started this way

#!/bin/bash mkfifo /var/run/out while true do cat /var/run/out | nc -l 8080 > >( while read line do do some stuff done ) done How can I get the pid ...
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58 views

Use minisat to find all solutions to SAT

I'm a unix noob and need a simple script in any language. I am solving SAT instances using minisat. The syntax is minisat inputfile outputfile. However, it only returns one solution. To find all ...
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1answer
18k views

bash: syntax error near unexpected token `('

I am trying to concatenate some files side by side. I use the pr command in the terminal. It works well, but when I use it in a shell script, I get the following error message: syntax error near ...
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2answers
5k views

Email using shell script

Is there a possibility to add multiple e-mails to a single variable so that when the shell script is run, it sends a mail to all the specified emails?
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60 views

how to get string between braces along with string without braces using awk

My input is: ABC_DFG_FRE s(DFR_GHY_JUY) BGR_KIU_PLO s(VFR_KJU_MKJ) output sholud be: ABC_DFG_FRE DFR_GHY_JUY BGR_KIU_PLO VFR_KJU_MKJ
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3answers
9k views

compare two columns of different files and print if it matches

I am using solaris 10 and Grep options involving -f doesnt work . I have two pipe separated files: file1: abc|123|BNY|apple| cab|234|cyx|orange| def|kumar|pki|bird| file 2 : abc|123| ...
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759 views

getting list of children processes by a background shell function

I have a bash script, in which I call function in a background: process_manager $1 $2 $3 & The function runs / executes commands that are passed as an argument in the background. How can I get ...
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1answer
59 views

Use a bash function in a pipelined command

I have a command similar to: ... | sort -u -V. Since some versions of sort do not support the -V flag, I thought it would be great if I made a function that conditionally adds the flag. But, it seems ...
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81 views

Problem in using user defined variable in a script

The following is a simple script, named myscript, that I wrote in order to run a command. dcmpath='$HOME/Data' dcmfile='IM1' dcm2nii $dcmpath/$dcmfile Unfortunately, bash does not recognize the ...
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483 views

Using Fifo hang script

out="$katalog/out" # wyjscie fifo="$katalog/fifo" # wejscie mkfifo $fifo touch $out [...] #k ./a.out <$fifo >$out & pid=$! [...] # get input line by line loop start echo "$liniain" >> ...
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134 views

Bash Script not deterministic in performing actions

I have a bash script which I invoke on system boot (Ubuntu 10.04) "Startup Applications". script: #!/bin/sh APP1='/home/ipc-display/development/projects/display-mgmt' ...
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3answers
2k views

XOR of a shell variable and a binary file

I have a password stored in a shell variable (which was read from command line input). I also have a keyfile stored in a file (which was created using dd and /dev/urandom). Since I want to require ...
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296 views

Shell Script Output not written to file properly

I tried to put the output of my program into a text file. It appends the echo commands to the file properly, but the imagemagick "compare" command is not appended to the file. It just STOUD's the ...
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1answer
51 views

insert value at the end of every record based on unique IDs

I have 2 files , one with Delimited and other one is Positional file. These two files shares same unique ID's as shown below but both the files contains different information. del.txt ...
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2answers
78 views

command condition sometimes integer sometimes string

I want to execute this condition while [ $(cat /path_of a file/) -eq 1 ] The condition is only correct if $(cat /path_of a file/) is an integer and not a string ! How can I overcome this ...
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1k views

Bash: split list of files into different files?

I have several files in a directory like: data1.dat data2.dat .... data24678.dat To run another code, I need to have a text file with the names of the files but I need to split in 50 files per ...
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772 views

How to write an alias function to make dd show progress bar?

According to this article, by replacing: $ dd if=/dev/sda of=/dev/sdb [additional options] with: $ pv -tpreb /dev/sda | dd of=/dev/sdb [additional options] one can augment the default dd ...
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57 views

Creating shell script on Desktop and not getting a prompt?

I have created a shell script on Desktop. Whenever I open it , I get a prompt to either run in terminal, display and etc. How to remove this prompt?
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98 views

What's the difference between print and head?

I know head gives you the beginning section of a file. But in this case, I'm trying to go through my source control and find every file that has a shebang line. And I'm failing to get results when I ...
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144 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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173 views

How can I tell what device or file name I am redirecting to

From within a shell script (sh/bash), how can I tell what device or file name I am redirecting to? For example, I have a shell script named script.sh. I run the shell script and redirect STDOUT to a ...
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1answer
2k views

Basename gives extra operand error

I 'm using the following script to merge few pcap files into one using mergecap command. But when I run it it gives me a 'basename: extra operand /mnt/md0/capture/DCN/dcn_2014_02_04_00_11_47_598.pcap' ...
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207 views

Is there a graphical shell or scripting environment for Linux?

I would like to draw my scripts and connect commands like blocks of functions (something similar to Yahoo Pipes). Does such an environment exist or do I have to develop it myself?
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490 views

How would I detect a non-login shell? (In Zsh)

I want to create a script that runs when a Zsh instance starts, but only if the instance is: Non-login. Interactive I think I'm right to say .zshrc runs for all interactive shell instances, ...
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3answers
1k views

How to get numbers by using regular expression, but only last one

In this example I can get 00. expr match "00 foo 99.jpg" '[^0-9]*\([0-9]\+\).*$' I want to know how to get last number from string, in this case 99 by using regular expression. The string may ...
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794 views

Cygwin - Shell Scripting (eval and echo)

I have the following file f1.txt: A=0 A=\`expr $A + 1\` and the following script file s1.sh for line in $(cat testfile.txt) do echo "$line" # eval $line done echo $A When I run the ...
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368 views

removing data from txt file

I have a comma-delimited giant file that was exported from a database. The file has this format Date,n1,n2,n3,n4,n5,n6,color,type,reference 10-Jan-2000,344,13,21,2,55,3,"rose garden" ,3444,32 ...
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239 views

Run a Shell script and read the output in a variable and run another script based on output

I am a novice to Linux system. My requirement is to run a Linux status script which echos a message (message is either "App is running" or "App is not running"). If the message is "App is running" ...