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

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1answer
92 views

How can I use a loop inside a command?

I'm writing a shell script that contains a command that takes multiple directories as space-separated input arguments (like ls). I would like to fill in those arguments from a variable but don't know ...
-2
votes
2answers
74 views

Input validation in a bash script [duplicate]

I've got the basics of bash scripting (I think anyways), and i'm trying to move on to more advanced stuff. I am trying to write a script that will perform input validation (the user must input either ...
0
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3answers
72 views

remove new lines

My input is a csv file like this: 10,"Special Projects,bangaram",0,,0 10,"Statutory/ Internal Audit , MO reporting (incl Excel Spreadsheet uploadation) ", bangaram,0,,0 10,"Complience with ...
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2answers
121 views

Creating a shell script that parses and redirects number into next command?

I am trying to create a script that kills an Xorg process. Here is an example of me running the commands in a terminal: First, I find the process id of the Xorg program (in this case, 2494): . ...
3
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1answer
106 views

shell Script: Sorting files into directories and subdirectories

I routinely write my notes in markdown in a complex directory structure like this. ~/doc/doc.md ~/doc/math/linearAlgebra/linearAlgebra.md ~/doc/math/linearAlgebra/numericalAnalysis.md ...
4
votes
4answers
420 views

Check for Process if Same is Running

Is there a script or a way in linux that when I try to execute a shell script/process, if the same is running, it will prompt that same is running and will exit otherwise it will continue.
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2answers
102 views

how to execute a python program in a shell script

I have a python program in that I wrote some python code (disk.py). I executed this program using the command python disk.py in a terminal, it worked. Now I want to execute it using a shell script.
0
votes
1answer
28 views

Capture Error of LS to file [duplicate]

#!/bin/sh if [ $(ls sample01.log | wc -l) = 1 ] then echo "File Found" > lsOutput.log else echo "File Not Found" > lsOutput.log fi But if sample01.log is not already existing my code already ...
4
votes
1answer
59 views

measure amount of data read from /dev/random

background I have written a collection of bash scripts (most of them in German only yet but if you are interested; download the archive not the single scripts) which help users create high-quality ...
3
votes
3answers
293 views

Adding a Column of values in a tab delimited file

How can I add a Column of values in a file which has a certain number of rows. I have a input file like this: Input file: SPATA17 1 217947738 LYPLAL1 1 219383905 FAM47E 4 77192838 SHROOM3 4 ...
1
vote
5answers
75 views

Replace instance of process in place?

I suspect this is not doable just because of the security implications, but here's what I'd like to do. Basically we run a bash shell-script on our CentOS server that calls Program-A (in our case ...
1
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3answers
134 views

What does “FILENAME=$(echo $INFILE | grep -oE ”[^/]+$“) ” mean?

FILENAME=$(echo /root/Source/code/script.sh | grep -oE "[^/]+$") I know that it would give me the file name from the file path here as script.sh. But can some one please explain me this?
0
votes
1answer
33 views

How to write simple if condition in ash?

I would like to write a small script that would check every once in a while if I have the internet connection. I would like to run it in crontab on my router where I have ash. I am having a hard ...
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votes
2answers
14 views

Shell script to format logs

Requirement : I need to write a script to find out for which API the request has been sent but no response received. Given below is an example of the logs i'll be working with. 2014-02-28 ...
1
vote
1answer
52 views

What is the Command to check the history of the command executed which should based on the user who accessed it [closed]

I am looking for the command or script to meet the following requirement. I wanted a history of all the users who connected to my machine and what commands they execute in there session and at which ...
2
votes
5answers
169 views

Quoting and escaping

I have a shell script, the arguments of which are collected in quote as a single argument and passed to a perl script. /usr/local/API/check_api.sh "-D x.x.x.x -C Test_Internal_Cluster -u user -p pass ...
1
vote
2answers
143 views

bash script error: source: not found

I must be missing a fundamental understanding about sourcing files in bash. I've tried the different approaches that seem like they should work, but I still get this error source: not found. In my ...
2
votes
3answers
57 views

How to optimize this oneliner? (if second column empty, put the line in another file)

I have a little "oneliner": while read ONELINE; do if [[ -n "`echo $ONELINE | awk '{print $2}'`" ]]; then echo "$ONELINE" >> LIST-ok.txt else echo "$ONELINE" >> ...
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votes
1answer
26 views

growing up with linux scripting and online resource to learn it [closed]

Is learning Linux shell scripting good for developing own career?I use linux and very much interested in scripting. Where should I start from?
2
votes
2answers
155 views

Read non-bash variables from a file into bash script

My bash script needs to read the variables from a text file that contains hundreds of variables, most of which conform to standard bash variable sytax (e.g., VAR1=VALUE1). However, a few lines in this ...
3
votes
2answers
112 views

Moving large numbers of files and directories to a different directory

I'm trying to move the following move a large number of files that exist in the following structure to a /mnt/originals but I need to maintain the structure at the same time. I know cp would be a ...
5
votes
3answers
91 views

reliable return code of background process

Let's assume the following piece of bash code: foo > logfile 2>&1 & foo_pid=$! while ps -p$foo_pid do ping -c 1 localhost done wait $foo_pid if [[ $? == 0 ]] then echo "foo ...
0
votes
2answers
73 views

Cron job is not working [closed]

i have a cron job center code hereonfigured at var/spool/cron/testuser, Am calling "adindex.sh" file from there. Am getting results when am directly put the command directly in prompt(php and sh), ...
0
votes
1answer
41 views

Combining two bash scripts by adding flags

I have two scripts which transform the code from software v.1 to software v.2 and viceversa. These are essentially a lot of sed substitutions. In the way I wrote them they accept two arguments: ...
1
vote
4answers
79 views

move file by list in file

I have a file the contain filenames, for example: /tmp/list.txt (it is with the spaces at the start of each line): /tmp/file.log /app/nir/home.txt /etc/config.cust I want, using one line, ...
4
votes
3answers
112 views

shell script problem with using the operators

I am comparing two strings using the levenshtein distance algorithm. I got the PHP implementation of the algorithm from here. I am calling this php implementation from my shell script as below. ...
4
votes
2answers
133 views

Dump process's stdin and stdout

I have two processes, let's say Parent and Child. Parent launches the Child and communicates with it through child's stdin and stdout. Parent <-> Child These processes use text protocol and I ...
14
votes
3answers
1k views

If I sudo execute a Bash script file, will all commands inside the Bash script be executed as sudo as well?

I want to write an automated post-installation script in Bash (called post-install.sh, for instance). The script will automatically add and update repositories, install and update packages, edit ...
4
votes
2answers
108 views

Shell Script to isolate files scattered in different folders

I need to write a shell script that traverses a given directory structure in multiple levels, recognizes the video files scattered in the folders and copies all of them to another single folder. The ...
6
votes
1answer
175 views

Parallel execution of bash script

I have a table URL_Experiment in my database (mySQL database). I have 2 million URL links in this table. For each URL, I am checking if some particular text is present in the URL and updating the ...
1
vote
1answer
60 views

what is $# used in a script for? [duplicate]

In many scripts in my organisation and even on online tutorials, this is a common if clause I come across : if [ $# -eq "somethng" -o $# -eq "somethng" ] what does this $# condition ...
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votes
1answer
28 views

Implementation Logic [closed]

I have two files,which is something like this: file1 msgid "New" msgstr "" dsvhuvchvdhcvhc msgid "Old" msgstr "hsvhs" kdnvcjdbvj msgid "Bold" msgstr "" file2 dcbjdsbc msgid "New" msgstr "Alas" ...
0
votes
2answers
78 views

Bash script to convert all *flac to *.mp3 with FFmpeg?

I want to convert all *.flac to *.mp3 in the specific folder. This is what I've tried, but not works: # change to the home directory cd ~/music # convert all *.flac files ffmpeg -i *.flac -acodec ...
0
votes
1answer
32 views

Getting a delimiter issue while executing the script

I am creating a test.sh file and i am running it as ./test.sh: string="hello" ed << EOF e any_file 1i ${string} EOF can anybody help me what it does? I am getting some delimiter issue. Can ...
1
vote
2answers
42 views

How can I substitute one command for another temporarily?

I'd like to alias sed to gsed, but only while a particular script is running. I have a script that invokes sed. On the Mac, BSD sed doesn't support the required features, but I don't want to replace ...
0
votes
2answers
30 views

Increment Daily Config Value

I have a configuration file that contains a lookback value, which I need to increment by +1 each day. IE: 60, 61, 62 etc.... It doesn't look like awk will work because of the formatting of the ...
5
votes
1answer
95 views

counting multiple patterns in a single pass with grep?

I've written a grep loop to iteratively count DNA trinucleotides within a gzipped DNA fasta file containing DNA sequences e.g. declare -a tri=(AAA AAC AAG AAT CAA .. etc) for i in ${tri[@]} do ...
2
votes
1answer
53 views

Monitor setup commands do not work in script

I'm running Arch Linux 64-bit on a Samsung RV511. I often connect external monitors using xrandr. As I run LXDE with Awesome as a window manager, I need to prepare the xrandr-command by killing ...
0
votes
0answers
32 views

Shell script use ssh forwarding to send a file to a second system

I have ssh forwarding enabled and ssh to server A. On server A I want to run a script as root and take advantage of the ssh key being forwarded for USER to send a file to system B. I'm getting a ...
1
vote
1answer
28 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 ...
2
votes
3answers
92 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
1answer
87 views

shell script construct array for file elements

I have a file named input_file which contains some lines. I need to remove certain characters in the line and store them in an array. So to remove the characters, I use the sed command and storing in ...
1
vote
2answers
41 views

Make Trickle get the correct $PATH

Trickle is a bandwidth limiting program. I have the following script for trickle. #!/bin/bash echo $PATH trickle -s -t 3 -u 200 -d 200 "$@" I have a script in ~/bin/ that want to run the script ...
0
votes
1answer
135 views

Basic script in Angstrom Linux running on a Beaglebone Black

On my embedded system, I can toggle a user led with: echo > 1 sys/class/leds/beaglebone:green:usr2/value. Similarly, I can find the value of a GPIO (gpio60) (set to input), with more ...
1
vote
3answers
78 views

Script to split string

@terdon's answer provides this script: find . -type f -name "*mp3" | while read file; do album="$(basename "$(dirname "$file")")"; filename="$(basename "$file")"; ...
2
votes
4answers
43 views

inline conditionals for assignment

Is there an "inline-equivalent" to expressions like the following?: if [[ $VERBOSE == 1 ]]; then V=$FOO else V= fi I'm thinking of something like this in perl, for example: $V = $VERBOSE ? ...
0
votes
1answer
233 views

“Expect” automation tool output to shell variable

#!/bin/bash # more commands here expect << EOD spawn telnet localhost 9151 expect -exact "Trying 127.0.0.1...\r Connected to localhost.\r Escape character is '^]'.\r" send -- "AUTHENTICATE ...
1
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3answers
50 views

Where to put wrapper scripts?

I created some scripts for administrative tasks etc, I made them to be independent from environment - every dependency is injected through arguments. However it is annoying to provide to script ...
1
vote
2answers
54 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 ...
1
vote
1answer
36 views

Automatically copy PDF.plugin to Chromium.app

I'm using Chromatic.app to update my Chromium.app recently. I'd like to use Chrome.app's PDF.plugin in Chromium.app. Therefore I need to copy PDF.plugin to the following directory: ...