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First of all, I would like to let you know that I am new to Linux. I did my search, but I don't really know what it is that I am looking for.
What I need is to make a simple program, that executes different commands one after another in terminal, because I don't want to run them by hand every time I need it. How do I make it? I suppose I can't just make an executable file that would trigger on double click, or can I?
Update:
When I posted this question I was just a kid who somehow managed to install a Linux based OS. I didn't know anyone else who had Linux or anyone in CS for that matter. I didn't have anyone to ask the "stupid questions". I didn't know how to express myself. I was looking for a shell script guide, but all I found for "linux programming" was C, which was way out of my depth then.
The simple program you are referring to is usually called a "shell script". Essentially, you just collect a number of commands you want in a file, and execute them. You can also have some sort of flow control (loops, if-else statements etc) for more complex scripts.
To build a simple bash shell script, let's call it myscript.sh, follow these steps:
At the first line of the "myscript.sh" source file put (see Note below)
#!/bin/bash
then your commands, for instance for demonstration purposes
echo "hello, I'm coming from the script file"
ls -l
Save the file.
To make this file "executable" type
$ chmod +x myscript.sh
and then you should be able to run this file from the command line with
$ ./myscript.sh
You'd see the output of the echo command "hello, I'm coming from the script file", followed by a directory listing in long format.
Here are links for a bash tutorial and a Bash Guide for Beginners.
Finally, sometimes you can just string a couple of commands together using aliases, though most people just "alias" shorter versions of common commands creating abbreviations for commands.
Note re location of bash:
To find out where your bash shell is you can always type which bash, it will return a path/directory, so put that at the top if it's different. For instance if it says /usr/bin/bash you'd put #!/usr/bin/bashthat in place of #!/bin/bash as the first line of your script.
try writing a shell script:
#!/bin/bash
command1
command2 | grep 'something' | pager
foo | perl -ne 'print'
Save is as something.sh.
Mark it as executable with chmod +x something.sh.
Then cd to the directory where it resides and run ./something.sh.
Whether you can double-click start your script it depends on your configuration, but as most scripts create text output this doesn't often make sense. Use .desktop files to create shortcuts to a single (!) command (or whatever filetype your Desktop Environment (gnome/kde/xfce) perfers).
If your needs go beyond some simple bash, take a look at scripting languages like the object-oriented Python or the classic *nix administration language Perl.
View #Levon's post for further details.
What you are looking for is a script. The most common type are written in bash. A nice alternative is to write them in python.
Have a look for bash scripting examples to get you started, or look into http://www.diveintopython.net/ to start with Python
Related
First of all, I'm using Ubuntu 20.04 and Python 3.8.
I would like to run a program that takes command line inputs. I managed to start the program from python with the os.system() command, but after starting the program it is impossible to send the inputs. The program in question is a product interface application that uses the CubeSat Space Protocol (CSP) as a language. However, the inputs used are encoded in a .c file with their corresponding .h header.
In the shell, it looks like this:
starting the program
In python, it looks like this:
import os
os.chdir('/home/augustin/workspaceGS/gs-sw-nanosoft-product-interface-application-2.5.1')
os.system('./waf')
os.system('./build/csp-client -k/dev/ttyUSB1')
os.system('cmp ident') #cmp ident is typically the kind of command that does not work on python
The output is the same as in the shell but without the "cmp ident output", that is to say it's impossible for me to use the csp-client#
As you can probably see, I'm a real beginner trying to be as clear and precise as possible. I can of course try to give more information if needed. Thanks for your help !
It sounds like the pexpect module might be what you're looking for rather than using os.system it's designed for controlling other applications and interacting with them like a human is using them. The documentation for it is available here. But what you want will probably look something like this:
import pexpect
p = pexpect.spawnu("/home/augustin/workspaceGS/gs-sw-nanosoft-product-interface-application-2.5.1/build/csp-client -k/dev/ttyUSB1")
p.expect("csp-client")
p.sendline("cmp indent")
print(p.read())
p.close()
I'll try and give you some hints to get you started - though bear in mind I do not know any of your tools, i.e. waf or csp-client, but hopefully that will not matter.
I'll number my points so you can refer to the steps easily.
Point 1
If waf is a build system, I wouldn't keep running that every time you want to run your csp-client. Just use waf to rebuild when you have changed your code - that should save time.
Point 2
When you change directory to /home/augustin/workspaceGS/gs-sw-nanosoft-product-interface-application-2.5.1 and then run ./build/csp-client you are effectively running:
/home/augustin/workspaceGS/gs-sw-nanosoft-product-interface-application-2.5.1/build/csp-client -k/dev/ttyUSB1
But that is rather annoying, so I would make a symbolic link to that that from /usr/local/bin so that you can run it just with:
csp-client -k/dev/ttyUSB1
So, I would make that symlink with:
ln -s /home/augustin/workspaceGS/gs-sw-nanosoft-product-interface-application-2.5.1/build/csp-client /usr/local/bin/csp-client
You MAY need to put sudo at the start of that command. Once you have that, you should be able to just run:
csp-client -k/dev/ttyUSB1
Point 3
Your Python code doesn't work because every os.system() starts a completely new shell, unrelated to the previous line or shell. And the shell that it starts then exits before your next os.system() command.
As a result, the cmp ident command never goes to the csp-client. You really need to send the cmp ident command on the stdin or "standard input" of csp-client. You can do that in Python, it is described here, but it's not all that easy for a beginner.
Instead of that, if you just have aa few limited commands you need to send, such as "take a picture", I would make and test complete bash scripts in the Terminal, till I got them right and then just call those from Python. So, I would make a bash script in your HOME directory called, say csp-snap and put something like this in it:
#/bin/bash
# Extend PATH so we can find "/usr/local/bin/csp-client"
PATH=$PATH:/usr/local/bin
{
# Tell client to take picture
echo "nanoncam snap"
# Exit csp-client
echo exit
} | csp-client -k/dev/ttyUSB1
Now make that executable (only necessary once) with:
chmod +x $HOME/csp-snap
And then you can test it with:
$HOME/csp-snap
If that works, you can copy the script to /usr/local/bin with:
cp $HOME/csp-snap /usr/local/bin
You may need sudo at the start again.
Then you should be able to take photos from anywhere just with:
csp-snap
Then your Python code becomes easy:
os.system('/usr/local/bin/csp-snap')
when I type the command stats.awk size.cvs, it says command not found on my virtual machine linux. Can someone help me get through sice Im new to linux and linux coding
It looks like you are not trying to run any standard Linux tool, but a script written by someone else called "stats.awk"... and the file you want to operate on is called "size.cvs" (it is more likely called size.csv -- as this is likely a "Comma Separated Value" file). Most Linux implementations do not allow you to just run a script unless the script is in your PATH and has the right permissions.
You could try "fully qualifying" the path of your awk script, but probably easiest is to just feed it into awk. Try:
awk -f stats.awk size.cvs
To find out more information about your shell run:
man $SHELL
Or just Google for a tutorial on your shell (which is likely bash). To find more about awk, again, try Googling for a tutorial on awk.
I was working on this tutorial here and I want to know the path so I can put it in my shell scripts on the top line as is good practice.
I was told this is not accurate:
echo "$SHELL"
What is the correct way to determine the path to the interpreter for shell scripts?
This is a shared hosting account and it is not obvious where it is located.
This is a follow up to a similar but not duplicate here.
You can use
which -a bash
to list all paths for the current user that point to a bash program.
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
I am trying to create a script that will run a program on each file in a list. I have been trying to do this using a .csh file (I have no clue if this is the best way), and I started with something as simple as hello world
echo "hello world"
The problem is that I cannot execute this script, or verify that it works correctly. (I was trying to do ./testscript.csh which is obviously wrong). I haven't been able to find anything that really explains how to run C Scripts, and I'm guessing there's a better way to do this too. What do I need to change to get this to work?
You need to mark it as executable; Unix doesn't execute things arbitrarily based on extension.
chmod +x testscript.csh
Also, I strongly recommend using sh or bash instead of csh, or you will soon learn about the idiosyncrasies of csh's looping and control flow constructs (some things only work inside them if done a particular way, in particular with the single-line versions things are very limited).
You can use ./testscript.csh. You will however need to make it executable first:
chmod u+x testscript.csh
Which means set testscript to have execute permissions for the user (who ever the file is owned by - which in this case should be yourself!)
Also to tell the OS that this is a csh script you will need put
#! /path/to/csh
on the first line (where /path/to/csh is the full path to csh on your system. You can find that out by issuing the command which csh).
That should give you the behvaiour you want.
EDIT As discussed in some of the comments, you may want to choose an alternative shell to C Shell (csh). It is not the friendliest one for scripting.
You have several options.
You can run the script from within your current shell. If you're running csh or tcsh, the syntax is source testscript.csh. If you're running sh, bash, ksh, etc., the syntax is . ./testscript.sh. Note that I've changed the file name suffix; source or . runs the commands in the named file in your current shell. If you have any shell-specific syntax, this won't work unless your interactive shell matches the one used by the script. If the script is very simple (just a sequence of simple commands), that might not matter.
You can make the script an executable program. (I'm going to repeat some of what others have already written.) Add a "shebang" as the first line. For a csh script, use #!/bin/csh -f. The -f avoids running commands in your own personal startup scripts (.cshrc et al), which saves time and makes it more likely that others will be able to use it. Or, for a sh script (recommended), used #!/bin/sh (no -f, it has a completely different meaning). In either case, run chmod +x the_script, then ./the_script.
There's a trick I often use when I want to perform some moderately complex action. Say I want to delete some, but not all, files in the current directory, but the criterion can't be expressed conveniently in a single command. I might run ls > tmp.sh, then edit tmp.h with my favorite editor (mine happens to be vim). Then I go through the list of files and delete all the ones that I want to leave alone. Once I've done that, I can replace each file name with a command to remove it; in vim, :%s/.*/rm -f &/. I add a #!/bin/sh at the top save it, chmod +x foo.sh, then ./foo.sh. (If some of the file names might have special characters, I can use :%s/.*/rm -f '&'/.)