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

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2
votes
2answers
158 views

Script to Recognize HDDs and run Smartctl

I'm thinking to do a script to recognize which HDDs are in use (sda, sdb, etc) and run a Smartctl on each one that's are in use, but I don't know how can I start, anyone can help me?
-2
votes
2answers
713 views

How to get the port number a program is listening on in a shell script? [closed]

I have a program (beam) running, and I need to figure out which TCP / IPv6 port it is listening on. I know netstat will tell me, but I haven't fully been able to parse its output: ...
3
votes
5answers
389 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 ...
0
votes
3answers
55k views

How to get IP Address using shell script? [duplicate]

Want to get the IP address using Shell script. Without knowing the eth0 or eth1 or eth2 How to get the particular IP address. I am not interest to get localhost address, want to get private IP ...
-4
votes
4answers
525 views

How to add a 3 lines in a file using shell script? [closed]

I have a file, that file contain 10 lines. And now I want to add 3 lines to end of the file using shell script. After add lines, If I run the script again I don't want to add same lines again. ...
3
votes
4answers
2k views

Bash script to output path to USB flash memory stick

How would I return (output) the path to any USB flash memory stick(s) connected to the local computer using bash (Ubuntu and Linux Mint)? Background: I'm providing users with an automated backup ...
4
votes
5answers
10k views

Command to display Memory usage, Disk Usage and CPU Load

I want to display Memory usage, Disk Usage and CPU Load in the following format: Memory Usage: 33/512MB (6%) Disk usage: 4.2/20GB (23%) CPU Load: 0.01 How do I do that?
3
votes
4answers
258 views

How do I make sure that a script is run exclusively? [duplicate]

So I have a bash scripts that does some things (pull from github, delete folders .. etc ..) pretty basic stuff. I usually run it whenever I need a new version of the web app on the server. The thing ...
1
vote
2answers
821 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 ...
8
votes
7answers
4k views

cron Vs. sleep - which is the better one in terms of efficient cpu/memory utilization?

The Case: I need to run some commands/script at certain intervals of time and for this I have two options - 1. set up a cron-job or, 2. implement a loop with sleep in the script itself. Question: ...
1
vote
0answers
78 views

Better approach to generating and adding contents to files

I have an input file like below. 1 First one 2 First two 3 First three 3 Second three I am generating 2 output files like below. #FILE1 1 First one 2 First two 3 First three #FILE2 1 ...
7
votes
4answers
13k views

Check if $REPLY is in a range of numbers

I'm writing a shell script for Linux, using Bash, to translate any video-file into a MP4. For that, I'm using avconv with libvorbis for audio. Inside my script, I have a question for the user : ...
2
votes
2answers
55 views

How to list all the files which were not created on Thursday

I need to delete old backups but I only want to keep Thursday Backups and delete the rest of the backups. Give me some kungfu tips. I'm on RHEL if that makes a difference.
0
votes
2answers
6k views

Are there any well known and well used shell scripting IDEs for Un*x?

Are there any IDEs targeted at shell scripting, specifically bash and zsh scripts? This means having syntax-highlighting for shell scripts and more importantly debugging environments with features ...
1
vote
1answer
60 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?
2
votes
1answer
793 views

Find out if files in a folder exist under other name in other folder

Possibly a little incorrect English ahead: There are at least 2 folders. For this, A contains files without extension, usually usernames, and B contains similar files, with '.yml' extension or ...
1
vote
2answers
101 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 ...
0
votes
1answer
101 views

Remove directory without `rm -r`

How to remove non-empty directory without using rm -r or find -delete ? I think it is related to unlink, perl or inode
1
vote
3answers
936 views

How to loop a read function in Bash Script?

I needed to remove spaces and capital letters to various strings of text like: "My Name is Mauro" -> "my_name_is_mauro" So I have created this bash script:lowercase_underscore.sh (call it the ...
6
votes
3answers
750 views

Remote ls on multiple machines

I want to connect to multiple machines specified in a file and perform 'ls' there. That's what I've come up with: for machine in $(cat machines) do echo "Connecting to " $machine ssh $machine ...
13
votes
2answers
15k views

Fastest way to concatenate files

I've got 10k+ files totaling over 20GB that I need to concatenate into one file. Is there a faster way than cat input_file* >> out ? The preferred way would be a bash command, Python is ...
5
votes
2answers
3k views

chmod + silent mode + how force exit code 0 in spite of error

Is it possible execute chmod and ignore error from command Example ( remark file.txt not exsist to show the example ) When I type chmod 777 file.txt I get error on the output chmod: cannot ...
0
votes
1answer
3k views

is there a “goto” like command in ksh

Here is my script: #!/bin/ksh #this is where I want to go again if user enter #an answer other than "yes or no" echo "yes or no?" read ans case $ans in [yY]*) echo "yes" ;; ...
2
votes
2answers
1k views

Shell script works when saved with nano but not when saved with Notepad++

I've been working on a bash script all day and have been testing on the machine I will be using it on. When I copy the script across from Notepad++ into a new file with nano editor inside SSH and ...
1
vote
2answers
367 views

Script always runs two instances

I was just curious, what may be the reason why script run two instances when executed. Whenever I run my script foo.sh, and when I check using: $ ps -ef | grep foo.sh It always returns two ...
1
vote
1answer
193 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 ...
-1
votes
2answers
3k 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
votes
3answers
95 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 ...
1
vote
2answers
229 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
votes
1answer
421 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
14k 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.
-3
votes
2answers
9k 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
420 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
213 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 ...
6
votes
3answers
19k 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 ...
2
votes
1answer
485 views

bash script - need date command variable

I am trying to create a script that will parse the /var/log/secure file for failed login attempts for today's date only and redirect those attempts into a separate file so I can view those attempts ...
2
votes
5answers
509 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
vote
3answers
733 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
1k 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 ...
0
votes
2answers
39 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 ...
2
votes
2answers
321 views

Bash script to signal a concurrently running instance (same script) about a condition and increment counter

Background Here's what I want to achieve. I have a (potentially) long-running process. Now I have locking in place just fine and all is generally in order. However, since this is a scheduled job, ...
1
vote
1answer
98 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 ...
3
votes
5answers
1k 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 ...
5
votes
2answers
9k 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
117 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" >> ...
8
votes
7answers
4k views

How to detect the desktop environment in a bash script?

I am writing a bash script that needs to know which desktop environment (XFCE, Unity, KDE, LXDE, Mate, Cinnamon, GNOME2, GNOME3,... ) is running. How can I obtain that information?
1
vote
0answers
56 views

manipulate a Drush “internal” variable

I want to modify a variable (preferably in a Bash Script format) because my PHP environment requires a port number. To show a URL in Drush containing a token that logs you in as user 1 (without a ...
-1
votes
1answer
52 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?
0
votes
1answer
94 views

Is it a bad idea to keep scripts in /root? [closed]

Is it a bad idea to keep scripts in /root? Simple bash scripts that have the following permissions: -rw-r--r-- They execute fine when ran as root, but is this bad practice? It's a multi-user system, ...
2
votes
2answers
3k 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 syntax (e.g., VAR1=VALUE1). However, a few lines in ...