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

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5answers
705 views

Replacing backslashes with commas in Bash

I tried writing a script in which I am reading through a file line-by-line. I am supposed to replace a backslash (\) with a comma (,). The input file is as follows: 1,2,3,WORKSTATION1\A,5 ...
1
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1answer
168 views

Illegal float value “error” c-shell

I have a form made it with a couple of text boxes, in which I input floating numbers and use this number to sum with other text box and put the result in a label. I then input the values of the text ...
0
votes
1answer
121 views

Bash- Help modify code for a custom output statement

The script will read the contents of a user-input file and count the number of employees with a specific job. Ex file line: Sophia Lewis, 542467, Accountant The script I have so far is: if [ -s ...
3
votes
3answers
1k views

Run nvm (bash function) via sudo

I want to write a init script that should basically run nvm use v0.11.12 && forever start /srv/index.js as the user webconfig. nvm is a shell function that is declared in ...
1
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2answers
11k views

How do I get absolute path from using find unix command

How to get absolute path by using find command. actually I am running the following script:- find . -size +20M | while read a do i=$(echo $a | sed 's:/: :g') echo $a; j=($i) ...
1
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1answer
52 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 ...
5
votes
2answers
404 views

Make a directory for each row within the given text file?

I'm trying to write a bash shell script that will read the data from a given (as an argument) file, and for each row in the file, make a sub-directory under the given (as an argument) directory. The ...
2
votes
2answers
3k views

Get running status of mongodb

Having a script where I start/stop various services depending on what I need. For example Apache, BIND, MySQL, PostFix, Memcached, Tomcat, ... and so on. Depending on status options to script etc. ...
5
votes
4answers
820 views

How do I break up a file like split to stdout for piping to a command?

I have a large .sql file full of SELECT statements that contain data I want to insert into my SQL Server database. I'm looking for how I could basically take the file's contents, 100 lines at a time, ...
2
votes
1answer
67 views

I'm trying to count and print song file names using awk as following

RANK NAME BAND YEAR GENERE DOMESTIC/INTERNATIONAL 206:Reach Out, I'll Be There:The Four Tops:1978:Pop:3/2 207:Bye Bye Love:The Everly Brothers:1950:Classic:3/2 ...
2
votes
1answer
124 views

Problem on running Script on host after connecting

I am new to linux scripting. Please help. I searched on below a lot but was not able to find appropriate answer : I am trying to make a script which I will later schedule as cronjob, so that it keeps ...
3
votes
3answers
182 views

How to do more than one substring replace at once in bash?

I have a directory contains image files that are to be echoed in bash. While echoing, I want to replace both file name and extension in single line command. Example files: images/file_name_1.jpg ...
0
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1answer
387 views

How to take incremental backup in tape drive

I am having 1 tape drive and I want to take incremental backup of 5 folder to the tape drive on every Friday. But the location of the five folders are on one server and the LTO mounted on a different ...
1
vote
1answer
73 views

Best way to determine piped command to shell script?

Given tree /some/directory | print.sh Is there any way for print.sh to know that "tree -f /some/directory" was called, without trying to parse pid processes?
1
vote
2answers
372 views

For loop in bash scripting [closed]

The following for loop in bash gives an error - line 42: 1 2 3 4 5 + 1: syntax error in expression (error token is "2 3 4 5 + 1") line 42 is statement - num1=$[$i1 + 1] for i1 in `seq 1 5` ...
5
votes
2answers
176 views

What's the difference between 'expansion' and 'substitution' in terms of shell programming's terminology?

Expansion and Substitution seems to be interchangeble at same context in shell programming language. For example, some documents such as Bash reference manual, Bash Hackers Wiki use the word ...
15
votes
5answers
695 views

Stateful bash function

I’d like to implement a function in Bash which increases (and returns) a count with every call. Unfortunately this seems non-trivial since I’m invoking the function inside a subshell and it ...
0
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1answer
1k views

How to track SFTP's error

I have 1 script which is used for SFTP. I am getting error for permission issue on target server. I want to track this error in log file. How i can track the sftp's error. below is my code, sftp ...
4
votes
1answer
499 views

How to create multiple tar files with bash script and use date as file names?

I have a lot of files and want to create an archive for every 100 files i.e. the first 100 files are in one tar file, and the 101st to 200th files are in another tar file. And I want to use the date ...
2
votes
3answers
123 views

Increment look back value within a configuration file daily +1

I have a configuration file that needs to be incremented daily. E.g. report.lookback.days.to.retrieve.data=60 This file contains multiple entries such as the one above that contains different ...
4
votes
2answers
1k views

Script to loop through folders with numeric names

I am working on a bash script to compress the images in my Wordpress folders. The wordpress folder structure is as follows: > wp-content/uploads/2014/01/filename.jpg > ...
2
votes
2answers
413 views

printf output running over into next line

I have created Bash SS in vi. My output is running over into the line below it. I am new to UNIX so I'm trying to learn. My output is displayed using printf. printf "%-15s %15s %15s %2d\n %2s " ...
16
votes
3answers
19k views

Variable as command; eval vs bash -c

I was reading a bash script someone made and I noticed that the author doesn't use eval to evaluate a variable as a command The author used bash -c "$1" instead of eval "$1" I assume using eval ...
0
votes
1answer
145 views

How to assign variable in awk

I have a code like below: $ awk -F'[]]|[[]' \ '$0 ~ /^\[/ && $2 >= "2014-04-07 23:00" { p=1 } $0 ~ /^\[/ && $2 >= "2014-04-08 02:00:01" { p=0 } ...
5
votes
2answers
386 views

Get the actions for a command programmatically

Let's take the git example: $ git<TAB><TAB> git git-import-dscs git-shell git-buildpackage git-import-orig git-upload-archive git-dch git-pbuilder ...
2
votes
1answer
123 views

Conditionals for fish shell

I am going through the fish shell tutorial and find that this simple if-else block does not work if grep fish /etc/shells echo Found fish else if grep bash /etc/shells echo ...
2
votes
1answer
1k views

How to check input parameter for running shell script [closed]

I'm writing a shell script to be used for various purposes. Various operations depend on input parameters. How can I check which parameter has been passed to the shell script while it runs? Can ...
0
votes
3answers
8k views

How to write a Java Program / Shell Script combination such that you can call the Java program as a remote command and yet supply a local file?

This is related to How to execute a remote command on a local file? I wrote a simple Java program that prints the first line of a file - import java.io.BufferedReader; import ...
8
votes
4answers
11k views

How to extract logs between two time stamps

I want to extract all logs between two timestamps. Some lines may not have the timestamp, but I want those lines also. In short, I want every line that falls under two time stamps. My log structure ...
2
votes
1answer
123 views

Multiplex bash function execution

I created a bash function to "automagically" connect on our switches and retrive their startup-config using the expect command. I have to use expect because this switch does not accept the ssh ...
1
vote
1answer
91 views

Shell script fails to run on startup

I want an executable program to run on startup. For this reason, I created a shell script: /etc/init.d/server. Then I run chmod +x name_of_script and update-rc.d server defaults. server (script): ...
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0answers
105 views

Execute commands on TMUX Detach

Is it possible to execute commands on tmux detach? I usually have a rails console and server running in the tmux session, on detach is it possible to automatically end those? Thanks.
1
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1answer
146 views

extracting specific substrings from string

I am trying to write a bash script. In a directory I have 2 fastq files: A-122-3.BH7WBVADXX.lane_1_P1_I24.hg19.sequence.fastq A-122-3.BH7WBVADXX.lane_1_P2_I24.hg19.sequence.fastq I just want to ...
1
vote
2answers
658 views

shell script to find the combination of the array elements

I have a shell script in which I have defined an array. The array contains more than 2 elements. I need to find the combination of all the elements in my array. Suppose, if my array has the elements, ...
1
vote
2answers
5k views

copy files from one path to another path in linux

I am new to linux. I am trying to copy files from one path to another path. I have a text file which has all names of files in the following pattern: file-1.txt file-2.pdf file-3.ppt .... I created ...
1
vote
2answers
4k views

Editing a Java properties file with Bash

I have the following Java properties file that is maintained by humans. # file.input = /very/old/name # file.input = /old/name file.input = /current/name file.input.default = /default/name ...
0
votes
0answers
42 views

How to find the currently running app from terminal on OS X?

I'm writing a shell script runs in the background and monitors user activity. I'd like to be able to capture current application/document if possible. Can I do that? (Cross-posting this from ...
1
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2answers
81 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 ...
3
votes
1answer
8k views

Bash command not found error

Why would the following script give following errors : ./check1.sh: line 10: Hi,: command not found ./check1.sh: line 21: syntax error: unexpected end of file check1.sh: #!/bin/bash subj="host ...
0
votes
1answer
254 views

Recursively delete hidden directory & its files?

I want to delete all hidden directoris from a directory and its sub-directory. I also use rm -rf .directory_name this command is iterative command I want to a recursive command. Please anybody help ...
1
vote
2answers
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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votes
2answers
70 views

How to delete a directory from terminal?

I'm trying to delete a directory after a series of events take place. That being said, I need to be able to place this in a file to execute once said events take place.
4
votes
3answers
463 views

How do I read the output of commands in a script

I'm learning Linux scripting at the moment, and one thing I can get working is assigning a command output to a variable. The command service httpd configtest returns Syntax is OK, so I wrote this. ...
8
votes
2answers
398 views

How do I elevate privileges in the middle of pipeline?

My guess was as follows: echo "Generating some text" | su - -c cat >/output/file But su says: su: must be run from a terminal What would you do?
0
votes
1answer
202 views

Can continually assigning a variable in a shell script cause a memory leak?

I've written a short script to copy Apache's server status to a log: #Save date and time to a variable dt=$(date) #Echo date and time to the log file as it's not included in server-status echo "Time ...
1
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0answers
92 views

Running a script after tty1 has loaded

I have been attempting to write a script to run dcled on start up, the program that runs this. I am using Debian Jessie with multiarch enabled. This is essentially a small file server. I am ...
4
votes
2answers
2k views

How to kill a process started as daemon?

I start a process using foo &. It outputs something like: [1] 16915 This is the process id, I guess. How can I store this number into a variable named MY_PROCESS_ID (for example)? Then I ...
23
votes
4answers
16k views

Using “${a:-b}” for variable assignment in scripts

I have been looking at a few scripts other people wrote (specifically Red Hat), and a lot of their variables are assigned using the following notation VARIABLE1="${VARIABLE1:-some_val}" or some expand ...
1
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1answer
161 views

mailx and HP-UX to RedHat migration

We are migrating some servers from HP-UX to Linux RedHat, and we have to migrate about 100 shell scripts that are referencing /usr/bin/mailx (instead of /bin/mailx on Linux). We'd like to change all ...
0
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2answers
235 views

Scripting Language Evolution [closed]

I have an assignment due Monday and I need some help because I have no knowledge on the subject and can't even understand what to search exactly. I am not waiting for an essay or something just some ...