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

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14
votes
9answers
461 views

Filter or pipe certain sections of a file

I have an input file with some sections the are demarcated with start and end tags, for example: line A line B @@inline-code-start line X line Y line Z @@inline-code-end line C line D I want to ...
0
votes
0answers
24 views

How to write shell script on shared application on one server to pickup specific customer PID for command processing? [closed]

I have a script which runs on a dedicated environment and processed the running PID to generate heap dumps. The problem I am having is on a shared environment where there are different customers ...
2
votes
4answers
97 views

How to make diff command ignore certain lines of second file(bash)?

For example: file1.txt: I need to buy apples. I need to run the laundry. I need to wash the dog. I need to get the car detailed. file2.txt I need to buy apples. I need to run the laundry. I need ...
-1
votes
1answer
34 views

Cron job * is replaced by file name in current directory [duplicate]

This is my first shell script program, so i think this is more likely a silly question for you all. Overview of problem My need is to write a shell command for installing our Node.js server. ...
2
votes
3answers
149 views

KSH/BASH Maximum size of an Array

What is the maximum size of array for ksh and bash scripting ? Example: Suppose I have an array of 10 elements than what will be maximum number of string count that a particular index of an array can ...
0
votes
1answer
44 views

Bash detect ascii art [closed]

For bash script, is there a easy way to detect if a text contains ascii art? An example of ascii art:
-1
votes
1answer
41 views

Replace mutiple strings with different values in a file using unix [duplicate]

I have a file in which the data is like below, 01,0000000,xxxxxxx/ 02,xxxxxxxx,yyyyyy/ 03,test1,41203016,,/ 01,0000000,xxxxxxx/ ...
0
votes
2answers
29 views

recording total runtime in bash script

I have the following script. When it runs it prints the Start and end Times to the file 'result.txt'. However, I also want to record the total runtime (end-start), but where I am doing echo runtine ...
0
votes
3answers
75 views

Remove special characters in a text file

I have a text file which contains in each line a sql query. For each line, I need to remove some special characters. Expl: if I have: select * from Users; insert into Users values ...
0
votes
0answers
22 views

KSH/BASH Comparsion b/w Two Array and then logical OR operation at other function (GNU bash 4.2 version)

I am new to unix and learning it basics. I wanted to compare same index of two different arrays and on the basis of comparision I wanted to put a data to other array. First I tried to use it ...
0
votes
1answer
46 views

How to accumulate data for the previous x number of days

Q: For the argument of the question, say today is 26/03/15. How can I 'accumulate' data for the last 5 days. But these dates are just an example. Ideally I would like to be able to accumulate data ...
4
votes
5answers
354 views

Script tries to create files even though it shouldn't have to?

I have a folder which contains some folders, these folder are moved very often so I made a script to see if they exist, and if not then create them. This is what I did to (which I though would) ...
3
votes
1answer
112 views

Why does `du -sh *` complain about invalid options?

I've searched my best through Google, but for the life of me I can't figure out what to use instead of * (asterisk) after a recent update (even Wikipedia seems to think du -sh * and du -sh * should ...
4
votes
3answers
228 views

KSH - if/then/else vs. double amps (&&) and double pipes (||)

I am wondering what are the best practices regarding if/then/else ; I tend to use the following form (because I find it easier to read) #!/usr/bin/ksh # [[ -f /path/to/target/file ]] && { ...
1
vote
1answer
37 views

read input from user in while loop having input and output redirection

This is my code: while IFS=',' read a b c; do read input echo $input done 3<&0 < input.csv > output.txt I took care of input redirection by redirecting through pipeline. But ...
0
votes
2answers
72 views

How can I filter ping results by time?

How do I filter out any pings that are under a certain ms, ie, only echo ping responses above 500ms to the text file? IP=$1 SECONDS_Between_Pings=$2 ping -i $2 $1 | while read pong; do echo $(date) ...
1
vote
3answers
65 views

UNIX KSH/BASH Call by Reference using Array (at GNU bash 4.2)

I am new to Unix shell scripting My code is as follows: i=0 for var in 'a' 'b' 'c' 'd' 'e' do content[i]=var ((i=`expr i+1`)) done a=10 b=50 c=40 d=90 e=100 Now I wanted to print the local ...
1
vote
2answers
56 views

Redirecting stdout and stderr of specific lines

I am reading a file and redirecting the entire output to a file. I would like to redirect stdout and stderr of certain expressions to screen as shown below (just an example): #!/bin/bash OLDIFS=$IFS ...
3
votes
3answers
51 views

Traverse, copy & transform file names

My issue: I need to copy log files, all with identical names, but stored 1-deep in subdirectories, and change their names. I'm copying from the a folder called Logfiles which contains a bunch of ...
0
votes
0answers
35 views

shell calling another shell program fails when run by crontab

I have scheduled to run the run.sh program like this: 16 09 07 * * root /opt/db_maintain/run.sh > /opt/db_maintain/temp-log and here is the run.sh: #/bin/bash #********* Saman ********* ...
2
votes
1answer
86 views

About executing shell script

Suppose I have a shell script file foo.sh. I can do chmod + x foo.sh and change it into an executable file. In Kernighan-Pike: Unix Programming Environment (UP) they show that after this typing ...
-1
votes
1answer
51 views

Generate a tarball or (.tar.gz) of the recently modified files in the directory

As the title says, I need help creating a linux script that generates a tarball or (.tar.gz) of all the files in the directory passed in as an argument to the script and have been modified in the past ...
2
votes
2answers
65 views

Tool to generate TCP traffic

I want to generate a TCP traffic starting from the port 0 to the port 65535. 1 tcp packet for each port with 1ms between 2 packets. The generator should not care if there is a TCP ACK or not. Are ...
1
vote
1answer
52 views

KSH/bash for File Creation Dynamically

I am new to ksh and unix and I am learning it: I wanted the following:I have a directory name tmp on that directory on basis of FileName Category I wanted to create 'n' number of files dynamically. ...
2
votes
4answers
126 views

How do I extract the first integer from text string in a column of a tab-delimited file?

I work in Medical Genetics and often have delimited text files where in one column (ex. column 5) there is a text string with a "mutation" in our jargon: c.2458C>T or c.45_46delAA or ...
0
votes
2answers
48 views

Check whether text contains non-ASCII characters in a shell script

I have a file, I want to determine if it contains only English ASCII characters. I thought this is a very common question, but when I googled it, there is no direct answer or related. According to ...
0
votes
1answer
44 views

How to change bash script output when the script is running?

I have the following loop which counts from 0 till 99: #!/bin/bash for ((i=0;i<100;i++)); do echo $i sleep 1 done Is there a way to change the result of the output from terminal while ...
17
votes
2answers
2k views

How did this '&' at the end of my command, make the script SO fast?

While solving some CTF challenges online, I came across a situation where I needed to bruteforce a server. This is the code I wrote: #!/bin/bash for i in {0..9}{0..9}{0..9}{0..9} do echo ...
3
votes
1answer
45 views

automate the process of fixing all broken links

There are lots of broken links in my system. I wrote a script to relink all broken links. But, after the scripts runs, find would again show me that the links still exists. This is my code: find ...
2
votes
2answers
170 views

how to check if both parameters are set in bash? [closed]

Say I have a executable bash file script.sh. I want to use it as ./script.sh p1 p2 p1 and p2 are two necessary parameters for this command. If either one of them is missing, the command should ...
2
votes
1answer
52 views

Using find and sed to copy 20th line of many files into one file

I have a folder called "PKA1" Within this folder I have several folders that look as: 1eV, 2eV .... 30eV Within each of these I have subfolders I have a file called PKA.dump I want to copy the ...
0
votes
2answers
75 views

Recursively remove files with idx > 10,000

The problem In the current working directory I have several (very many) folders and some of them have lots (like 100,000+) of files inside. My goal is getting just the folder with 10,000+ files and ...
1
vote
2answers
51 views

Debian: umount /media/usb0: “Operation not permitted”

I recently moved from Ubuntu 14.10 to Debian Testing. Under Ubuntu I had a shell script for backing up my home folder to a USB stick. The last line of the script unmounts the USB stick. Adapting it to ...
4
votes
2answers
139 views

Increment a variable using a Bash script

I have a file that contains the following text. // // test_file.h // test project // // Created by Test User // #ifndef test_file_constants_h #define test_file_constants_h // Generic includes ...
-1
votes
0answers
13 views

Process2 not taking control over process1

I have a device which has two cli consoles.One console say Xwhich comes by default when device comes up. My task is to start another console say Ybased on a condition say if variable has value=start2 ...
2
votes
4answers
115 views

How can I find the program I'm hiding in bash

Say I have PATH="home/bob/bin:/usr/bin". I am writing a bash script /home/bob/bin/foo that will do some munging and then call /usr/bin/foo. Of course I want to be able to use this script on ...
1
vote
2answers
53 views

sed - doesn't append new line EOF and replaces letter not defined

I am experiencing a strange behavior using a sed command (got to be sed, no awk in this case) and got two questions for you, hoping someone got the skills to explain me what I am doing wrong. I want ...
1
vote
2answers
54 views

Splitting the working directory in a bash script

If a do: IFS="/" read -ra PARTS And type in a path manually, it creates the array "PARTS" as hoped, however: IFS="/" read -ra PARTS <<< $(pwd) creates an array with a single element, ...
3
votes
3answers
160 views

Variable not expanding inside another variable bash

I am reading a csv file in bash script as follows: resource='/data/bscs/' while IFS='|'read seqid fname fpath do echo "FILENO: $seqid" echo "FILENAME: $fname" echo ...
1
vote
1answer
59 views

Unix Shell : Array assignment not working [duplicate]

I am new to unix shell I am learning array by following code source_array_list[0]="a" source_array_list[1]="a" source_array_list[2]="a" source_array_list[3]="a" source_array_list[4]="a" ...
1
vote
1answer
45 views

Unable to track error

I am new to Unix shell scripting, While running my program I found the following errors today.ksh[36]: test: 0403-004 Specify a parameter with this command. sed: 0602-419 Cannot find or open file ...
0
votes
1answer
43 views

Error while passing variables for keyword match using sed

I am a beginner in scripting. I am writing a bash script for text processing where this command is giving me error: sed -e "/\<$7\>/ /\<$5\>/$6/" < "$2/$1" > "file.tmp" This is ...
-1
votes
0answers
27 views

Can we connect Winscp using power broker?

I am connecting through power broker i.e pbrun command via putty to server. Can someone guide me, How can I connect to the server if I am using WinSCP because authentication will be done only I ...
1
vote
2answers
33 views

Script to do periodic printing

I have a networked inkjet printer (HP all-in-one photosmart 5510), and currently I have a simple script that reminds me periodically to send a small job for printer so that the ink doesn't dry up. I'm ...
3
votes
3answers
113 views

Bash : Native way to get rid of quotation around each array member

I read an array from another script. This array needs to put " " around all array members since some members are empty. in_file=./data vector=($(./readdata.sh 0 $in_file)) for index in ${!vector[@]} ...
1
vote
3answers
42 views

how to execute commands on remote server as different user

I am trying to connect to server B from server A using ssh and executing commands using some other user. However, when I try searching for a pattern in log file it says "cannot open log file" below is ...
1
vote
2answers
39 views

Bash script strange behavior with echo - printf in a file

I want to print part of the content of a .csv file in another file if there is a match with some condition: The csv content is like this abc test;ABCtest.it xyz test;XYZtest.com I read the content ...
1
vote
1answer
58 views

How can I skip empty files with sed?

I am using sed like this: sed -e 's/ *| */|/g' ${array_export_files[$loopcount]}>>$TEMPDIR/"export_file"_${testid}_${loopcount}_$$ under a while loop but problems come when the file is ...
0
votes
1answer
55 views

Expect Scripts - Reading from Files and Accepting User Input

How can I write an "Expect" script to: 1) iterate over a list of IP addresses and log in to each to perform commands (like in a BASH for loop). Right now I just copy/pasted the few lines that are my ...
1
vote
1answer
32 views

Match closest equal or preceding timestamp

I have a series of timestamps representing events, e.g.: 20150401_1120 // event a 20150401_1211 // event b And a series of logfiles, each representing a fixed period of time and timestamped ...