A script is a sequence of commands or instructions that are executed by an interpreter program rather than compiled into a standalone executable program.

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450 views

stdout , stderr and logging using the script command

I have remove.sh which contains: rm -v test.tmp And I have install.sh which contains: script remove.log -c './remove.sh' What can I do so that whether or not test.tmp exists, I don't see any rm ...
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1answer
76 views

bash shell - how to do nested loop without “syntax error: operand expected” [duplicate]

I am trying for i in {4..100} do is_prime=true a=$(($i-1)) for divider in {2..$a} do b=$(($i % $divider)) # <-- line 9 [ $b -eq 0 ] && echo 'y' #is_prime=false done [ ...
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1answer
264 views

How do you keep the password hidden when invoked during the su command?

This is the first time it has happened to me where I am using the su command and it actually displays the password on the terminal and doesn't stay hidden. Here is my code snippet: sshpass -p ...
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0answers
37 views

convert many eps files in a single pdf or ps file using shell scriptI

I have SSt12.OLR.1.eps, SSt12.OLR.2.eps SSt12.OLR.3.eps SSt12.OLR.4.eps ......and covert these eps files into single pdf or post script file. please suggest a shell script.
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2answers
5k views

Run a script at startup

I am using Ubuntu 14.04. I wrote a small script named trial. The contents of the script are as follows: #!/bin/sh SHELL=/bin/sh PATH=/bin:/sbin:/usr/bin:/usr/sbin sh -c firefox I copied the ...
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2answers
1k views

Need help to make rows into column with awk or sed

Recently, I look for scripts to take this: This; Is; First; Line; and make it like: This Is First Line
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2answers
254 views

Autentification on SSH connection in OneLine [duplicate]

Possible Duplicate: Shell Script for logging into a ssh server I need to connect via SSH to a remote server, however I must do this with out interactive mode and with out use Public keys ...
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1answer
82 views

just wanted to know what am i doing wrong in the end of this script that doesnt put my checkdate in to cal command

#Purpose: Validate a date #Usage: chkdate year month day # if [ $# -eq 0 ]; then echo Usage: chkdate year month day exit 0 fi year=$1; month=$2; day=$3; extra=$4 if [[ "$extra" != "" ...
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3answers
14k views

What does it mean to have a $“dollarsign-prefixed string” in a script?

I just saw this in an init script: echo $"Stopping Apache" What is that dollar-sign for? My research so far: I found this in the bash manual: extquote If set, $'string' and ...
12
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7answers
2k views

Practical tasks to learn shell scripting

I'm looking for some common problems in unix system administration and ways that shell scripting can solve them. Completely for self-educational purposes. Also I'd like to know how would you go about ...
15
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7answers
11k views

Faster way than ping for checking if computer online?

I'm writing a wake on lan script for a set of our lab computers. We have sqlite db with a list of the computer hostnames, IPs, and MACs and currently I ping each of them with '-c1' so it doesn't run ...
12
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6answers
6k views

What are good online resources for learning shell scripting? [closed]

I am a beginner to shell scripting. I have not yet hardly coded a single program, but I am interested in learning it completely. Can anyone suggest some good online resources which will guide me?
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1answer
7k views

How to automatically record all your terminal sessions with script utility

What I want to achieve is be able to record my terminal sessions to file automatically whenever I use Yakuake/Konsole. It's easy to achieve if at the start of my session I do: script -f ...
7
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2answers
37k views

how can I add (subtract, etc.) two numbers with bash?

I can read the numbers and operation in with: echo "First number please" read num1 echo "Second mumber please" read num2 echo "Operation?" read op but then all my attempts to add the numbers fail: ...
9
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1answer
1k views

confirmed exit using trap

I am trying to trap the Ctrl+C signal asking a confirmation from the user. The trapping part works fine. But once the signal gets trapped, it does not return to the normal execution. Instead, it quits ...
9
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3answers
4k views

The way to use `/usr/bin/env sed -f ` in shebang?

Typing /usr/bin/env sed -f in terminal works. But if use it as a shebang, #!/usr/bin/env sed -f s/a/b/ The script will be fail to execute: /usr/bin/env: sed -f: No such file or directory I ...
6
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5answers
654 views

Modify a file without creating another file

Is there a way to modify a file without writing the contents to other file, without sed and awk? For example, $ cat test.txt aaa aaa bbb ccc ddd Replacing using sed with -i option, sed -i ...
6
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1answer
3k views

Increase %e precision with /usr/bin/time shell command

When I run the time command in shell time ./myapp I get an output like the following: real 0m0.668s user 0m0.112s sys 0m0.028s However,when I run the command \time -f %e ./myapp I lose ...
4
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2answers
521 views

Shell script printing the most visited directories

Is there a way to write a bash script with the following functionalities? Be launched when I press some key or key combination. (not so important requirement) Identify the 7 most visited directories ...
11
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3answers
768 views

How do you continue a sentence with a command inside

For example, I have been trying to say "There are 10 people online at the moment" in my script file. I can never seem to get the command working without the "people online at the moment" part on the ...
8
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3answers
4k views

End sox recording once silence is detected

I'm writing a script that uses sox to record me talking. Now I need sox to wait until it detects sound before it begins recording, and I do have that figured out. But I also need sox to exit once ...
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4answers
5k views

Parallel execution of a program on multiple files

I have a small script that loops through all files of a folder and executes a (usually long lasting) command. Basically it's for file in ./folder/*; do ./bin/myProgram $file > ./done/$file ...
7
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2answers
22k views

su options - running command as another user

I was wondering how to run a command as another user from a script. I have the script's owner set as root. I also have the following command being run within the script to run the command as the ...
5
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4answers
221 views

Prefixing and appending blocks of text to a list of files

I'm trying to prefix and append blocks of text to a list of files. Here is where I am so far. The sticking point is the sed -i "1i \$prefix" "$file" && line. sed won't substitute the value of ...
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5answers
11k views

Parsing a delimited text file in bash as command arguments

I have a text file split up like so: field1,field2,field3 xield1,xield2,xield3 dield1,dield2,dield3 gield1,gield2,gield3 Each of these columns will be a parameter to a program, and I would like ...
3
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2answers
362 views

split a file, pass each piece as a param to a script, run each script in parallel

I have a words.txt with 10000 words (one to a line). I have 5,000 documents. I want to see which documents contain which of those words (with a regex pattern around the word). I have a script.sh that ...
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1answer
1k views

Shell script filtering through jpg files attributes

I'm trying to find a way to filter through thousands of jpg files, and keep only the files with a certain attribute (such as the camera brand with which the picture was captured). How can I do so?
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3answers
9k views

Invert boolean variable

I want to try simple script flag=false while !$flag do read x if [ "$x" -eq "true" ] then flag=true fi echo "${x} : ${flag}" done But when i run it, if i type true, i will see ...
7
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2answers
1k views

sync files recursively between two folders where files are less than 24 hours old

I want to find all the files under a directory which are within 24 hours then rsync those files with another server. There are some old files that I do not want to transfer, however if those old ...
7
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6answers
6k views

Extracting nested zip files

I have numerous zip archives, each of which contains a number of zip archives. What is the best way to recursively extract all files contained within this zip archive and its child zip archives, that ...
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3answers
2k views

How to iterate through a list of files with spaces that is sorted (case insensitive)?

I am doing this in OSX which uses bash but obviously, not all bash conventions are used so hopefully your suggestion is available to me :) I have the following files fun bar1.txt Foo bar2.tXT ...
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1answer
99 views

How can I get information about my virtual desktops via the command line?

I'm curious how I can get information such as the dimensions of my desktop, which desktop is currently active, and what labels (if any) are set for my desktop enviornment (DE).
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1answer
2k views

Changing password in multiple boxes using script

I'm working in a environment which has around 400 AIX boxes. I don't have root access and I'm a normal user. The environment has no LDAP kind of centralized mechanism for authentication so the ...
3
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5answers
349 views

How can I force a script to use more resources?

I'm running a very time-consuming script which takes many hours to end. Watching top I see that it's only taking 5% of the CPU at best, usually around 3%. Is there any way to force the script to use ...
3
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3answers
215 views

Permissions for a submission script

I'm a TA for an introductory Python programming class (all work is done from the terminal), and I'm writing a project submission script. Ideally I want a directory setup like this: submissions/ ...
3
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2answers
796 views

Convert a typescript file to a list of commands (history)

I wanted to record a linux session so I could use it as documentation for a "how to install" guide. I found something on the internet that suggested that the script command would be good for this, and ...
2
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3answers
124 views

Processing input line by line (with empty lines) from shell

In a shell script, I need to parse the output of a command line-by-line. The output may include empty lines, and these are relevant. I am using ash, not bash, so cannot resort to process substitution. ...
2
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1answer
125 views

Get the full window dimensions (including decorations) in Unity

I have used the answer to How do I find the window dimensions and position accurately including decorations? in my bash scripts, and had good success with my Silentcast application on Xfce, but now ...
2
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3answers
1k views

Extracting characters after a particular text

I am extracting a page from website using cURL command. curl "www.google.com" -s | w3m -dump -T text/html > foo.txt The w3m command outputs the HTML page in a much more simpler format so that ...
2
votes
2answers
2k views

Concatenate multiple files under subdirectories

My directory structure is given below x:\Project_2012-158A\Sample_4041 SampleSheet.csv 4041_CGTACG_L002_R1_001.fastq 4041_CGTACG_L002_R2_001.fastq 4041_CGTACG_L006_R2_001.fastq ...
2
votes
4answers
2k views

Anacron job complains “Gtk-WARNING **: cannot open display”

I'm trying to make a simple weekly Anacron job that backs up my computer if I click yes on the dialog. The script I wrote works fine if run manually, but when Anacron runs it, nothing happens and I ...
1
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1answer
50 views

Neutralisation of data from Windows to Unix

I just noticed that other platforms files (Windows) had to cause me many bugs, like here, in my regexes. Mostly, the line ending ^M. There seems to be many ways to do dos2unix, like here described. ...
1
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1answer
59 views

How to write this replacement with condition

I want to replace now within my working directories the word -> with $\to$ if the word is not within verbatim environment. Pseudocode Replace all entriens of -> with $\to$ everywhere else but not ...
1
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2answers
134 views

How to notice log file changes with Linux standard tools? [duplicate]

I need something that does not need to be installed. It's on an embedded system with very little space on the HD. I can't instal anything. I need to do it with something that is already included. I ...
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2answers
1k views

How can I queue processes?

I have a surveillance camera and a program records videos when motion is detected. Basically, this program saves the video in a very heavy format. My solution was to call a script that converts the ...
8
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2answers
773 views

How to non-invasively test for write access to a file?

In a shell script, how do I easily and non-invasively test for write access to a file without actually attempting to modify the file? I could parse the output of stat, but that seems really complex, ...
7
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1answer
1k views

Problems running python script from motion

I'm trying to set up the raspberry pi with my webcam as a motion detecting cctv that uploads the videos to google drive using Jeremy Blythe's script I have motion working correctly and the python ...
6
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3answers
5k views

Execute a command on user logon

In Linux desktop system, I want to execute a command when the user logs in. After reading some other posts, I tried to insert the command in ~/.bashrc but unsuccessfully. Moreover, the system uses a ...
6
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1answer
444 views

Capabilities for a script on Linux

If I want to set a capability (capabilities(7)), such as CAP_NET_BIND_SERVICE, on an executable file and that file is a script, do I have to set the capability (setcap(8)) on the interpreter starting ...
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4answers
5k views

Can IFS (Internal Field Separator) function as a single seperator for multiple consecutive delim chars?

Parsing an array using IFS with non-whites space values creates empty elements. Even using tr -s to shrink multiple delims to a single delim isn't enough. An example may explain the issue more ...