Scripting Linux to install several programs at once - linux

I've been installing step by step video conversion codec and tools for a few hours now, and it is just plan annoying. Is it possible to design a script to load in linux to do all the commands in sequence one after another?

Absolutely. Create a plain text file, put #! /bin/bash at the top, then write all the commands in the file. Save it, "chmod +x yourFile", then run it by calling ./yourFile.
If your installs are a more intricate, I'd need to see an example to say more specifically how to do this as a shell script.

Related

Cannot find chmod[metasploit installation]

in the picture below you can see that it says chmod command is not found yet it has chmod installed. I am installing metasploit directly from the terminal(I did not install any desktop environment and don't want to run msf from there). Is there any way to solve this? I would gladly appreciate any replies.
Instead of using that command, use this instead
curl https://raw.githubusercontent.com/rapid7/metasploit-omnibus/master/config/templates/metasploit-framework-wrappers/msfupdate.erb > msfinstall && chmod 755 msfinstall && ./msfinstall
Remove the backslashes from the composite Bash command, they're used in Linux to escape the space character. For example, ỳou would have to type:
cd ~/Documents/My\ Folder
to access
~/Documents/My Folder
By writing the command the way you did you were looking for the ' chmod' command instead of 'chmod', you've basically inserted a space before the command name.
I'd suggest studying Linux Bash scripting before venturing into Metasploit.
You would otherwise continually stumble against this kind of issues, also if you'd like to work with Metasploit from its command console it's pretty much mandatory to study Linux Bash scripting (and the Linux OS as a whole).

Creating multi-threading in Linux

I have a Linux computer and want to do the following (two independent actions/processes if possible):
Run a series of CLI commands every x minutes towards a remote computer to see if a file exists there. If it does, I want to start downloading this file to one of my directories. The files could be big and there might be many remote computers, so ideally I should treat each connection as an own process.
Check to see if a new file has arrived in my file system. If it has, I want to go through this file, analyze the content with some algoritms and then store the result in a database that I have installed. Then delete the file that was analyzed.
Any recommendations on how to do this the "best" and most reliable way? Scripting? Java/C/etc? Multi threading or just a single process that is looping through the content? The result should be something that should run for months without stopping.
Any suggestions and/or sample code very welcome!
Thanks!
Z
For #1, you can use crantab(http://unixhelp.ed.ac.uk/CGI/man-cgi?crontab+5) to run your script.
I think you can use Shell, Python, Ruby to complete your tasks
for downloading you can use a mix of something like that script (not tested and incomplete):
function download_and_analyze(link){
Z=mktemp
cd $Z
wget -c -t0 -q -C $link
# analyze algorithm here
cd /tmp
rm -rf $Z
}
for A in $REMOTEFILE; do
download_and_analyze($A) &
done
this is just a scratch to you implement it as a shell script. Realiability is guaranteed by wget.
you also can use rsync if it's on another computer acessible by ssh.
cheers

How to create an executable for a shell script in Ubuntu?

I have written a simple Shell script named decBright.sh that decreases my screen brightness by a bit every time I run it. However, I do not want to open the terminal and execute bash decBright.sh every single time.
Instead, I want to create some kind of executable file that I can place on my Desktop, which will run my script when it is double-clicked. One answer I found here on the askUbuntu forums did not work for me.
Is there some other way to do it?
I am using Ubuntu 14.04 (Trusty Tahr)
An executable in linux is a file with the executable bit on. Thus you simply modify it with chmod:
chmod +x decBright.sh
Then you can run it with:
./decbright.sh
You can also run it by double-clicking in many graphical linux distributions.
You also better provide a "Shebang": the first line of your script should specify the "interpreter":
#!/bin/bash
Or any other interpreter (at the first line of your file).

Linux version of a .cmd file

I am creating a terminal program and cannot find out what the ending is for Linux. I know in windows it is .cmd. Any help would be great.
Thank you.
Yes, you can remove the .sh at the end and it should work, generally using ./cmd will get it to run. this goes for C programs as well. You do not need to give an extension for the object file, You could then add a path to your bash file and then you can execute it as a normal command.
Look here.
https://stackoverflow.com/a/8779980/2720497
You don't need a file extension on Linux, though typically, people use .sh (sh being short for 'shell').
You can run it one of two ways:
bash myscript.sh
or you can make the script itself executable and run it directly:
chmod a+x myscript.sh # make it executable
./myscript.sh # run it
Linux scripts' first line is typically #!/bin/bash which is the path to the specific shell used to run the script with the second method.

What's a .sh file?

So I am not experienced in dealing with a plethora of file types, and I haven't been able to find much info on exactly what .sh files are. Here's what I'm trying to do:
I'm trying to download map data sets which are arranged in tiles that can be downloaded individually: http://daymet.ornl.gov/gridded
In order to download a range of tiles at once, they say to download their script, which eventually leads to daymet-nc-retrieval.sh: https://github.com/daymet/scripts/blob/master/Bash/daymet-nc-retrieval.sh
So, what exactly am I supposed to do with this code? The website doesn't provide further instructions, assuming users know what to do with it. I'm guessing you're supposed to paste the code in to some other unmentioned application for a browser (using Chrome or Firefox in this case)? It almost looks like something that could be pasted in to Firefox/Greasemonkey, but not quite. Just by a quick Google on the file type I haven't been able to get heads or tails on it.
I'm sure there's a simple explanation on what to do with these files out there, but it seems to be buried in plenty of posts where people are already assuming you know what to do with these files. Anyone willing to just simply say what needs to be done from square one after getting to the page with the code to actually implementing it? Thanks.
What is a file with extension .sh?
It is a Bourne shell script. They are used in many variations of UNIX-like operating systems. They have no "language" and are interpreted by your shell (interpreter of terminal commands) or if the first line is in the form
#!/path/to/interpreter
they will use that particular interpreter. Your file has the first line:
#!/bin/bash
and that means that it uses Bourne Again Shell, so called bash. It is for all practical purposes a replacement for good old sh.
Depending upon the interpreter you will have different languages in which the file is written.
Keep in mind, that in UNIX world, it is not the extension of the file that determines what the file is (see "How to execute a shell script" below).
If you come from the world of DOS/Windows, you will be familiar with files that have .bat or .cmd extensions (batch files). They are not similar in content, but are akin in design.
How to execute a shell script
Unlike some unsafe operating systems, *nix does not rely exclusively on extensions to determine what to do with a file. Permissions are also used. This means that if you attempt to run the shell script after downloading it, it will be the same as trying to "run" any text file. The ".sh" extension is there only for your convenience to recognize that file.
You will need to make the file executable. Let's assume that you have downloaded your file as file.sh, you can then run in your terminal:
chmod +x file.sh
chmod is a command for changing file's permissions, +x sets execute permissions (in this case for everybody) and finally you have your file name.
You can also do it in your GUI. Most of the time you can right click on the file and select properties; in XUbuntu the permissions options look like this:
If you do not wish to change the permissions, you can also force the shell to run the command. In the terminal you can run:
bash file.sh
The shell should be the same as in the first line of your script.
How safe is it?
You may find it weird that you must perform another task manually in order to execute a file. But this is partially because of a strong need for security.
Basically when you download and run a bash script, it is the same thing as somebody telling you "run all these commands in sequence on your computer, I promise that the results will be good and safe". Ask yourself if you trust the party that has supplied this file, ask yourself if you are sure that you have downloaded the file from the same place as you thought, maybe even have a glance inside to see if something looks out of place (although that requires that you know something about *nix commands and bash programming).
Unfortunately apart from the warning above I cannot give a step-by-step description of what you should do to prevent evil things from happening with your computer; so just keep in mind that any time you get and run an executable file from someone you're actually saying, "Sure, you can use my computer to do something".
If you open your second link in a browser you'll see the source code:
#!/bin/bash
# Script to download individual .nc files from the ORNL
# Daymet server at: http://daymet.ornl.gov
[...]
# For ranges use {start..end}
# for individul vaules, use: 1 2 3 4
for year in {2002..2003}
do
for tile in {1159..1160}
do wget --limit-rate=3m http://daymet.ornl.gov/thredds/fileServer/allcf/${year}/${tile}_${year}/vp.nc -O ${tile}_${year}_vp.nc
# An example using curl instead of wget
#do curl --limit-rate 3M -o ${tile}_${year}_vp.nc http://daymet.ornl.gov/thredds/fileServer/allcf/${year}/${tile}_${year}/vp.nc
done
done
So it's a bash script. Got Linux?
In any case, the script is nothing but a series of HTTP retrievals. Both wget and curl are available for most operating systems and almost all language have HTTP libraries so it's fairly trivial to rewrite in any other technology. There're also some Windows ports of bash itself (git includes one). Last but not least, Windows 10 now has native support for Linux binaries.
sh files are unix (linux) shell executables files, they are the equivalent (but much more powerful) of bat files on windows.
So you need to run it from a linux console, just typing its name the same you do with bat files on windows.
Typically a .sh file is a shell script which you can execute in a terminal. Specifically, the script you mentioned is a bash script, which you can see if you open the file and look in the first line of the file, which is called the shebang or magic line.
I know this is an old question and I probably won't help, but many Linux distributions(e.g., ubuntu) have a "Live cd/usb" function, so if you really need to run this script, you could try booting your computer into Linux. Just burn a .iso to a flash drive (here's how http://goo.gl/U1wLYA), start your computer with the drive plugged in, and press the F key for boot menu. If you choose "...USB...", you will boot into the OS you just put on the drive.
How do I run .sh scripts?
Give execute permission to your script:
chmod +x /path/to/yourscript.sh
And to run your script:
/path/to/yourscript.sh
Since . refers to the current directory: if yourscript.sh is in the current directory, you can simplify this to:
./yourscript.sh
or with GUI
https://askubuntu.com/questions/38661/how-do-i-run-sh-scripts/38666#38666
https://www.cyberciti.biz/faq/run-execute-sh-shell-script/
open the location in terminal then type these commands
1. chmod +x filename.sh
2. ./filename.sh
that's it

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