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.
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).
I want to search my access logs for traffic going to a directory on a Linux. I have a mac which I know I can do this with my terminal but I can't find an example how to do this.
Do you have the log locally on your Mac? Or are you asking how you would use a Mac to administer a Linux OS?
Open terminal, either change directory to the dir that contains the log or adjust the command to suit. Depending on what you want to search for, you'd use grep.
grep -i "dir name" logfile.log
It's a bit of a wide empty question so I don't know what you want to search for.
If it's remote, you'd open terminal and ssh to the server which has the log and do something similar to the above. Or, if you're asking how you would do it in one command, you could use ssh too.
ssh user#linux "grep something /var/log/apache/access.log"
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
While writing BASH scripts, I generally use the which command of a Linux machine (where Linux Machine refers to Desktop based Linux OS like Ubuntu, Fedora, OpenSUSE) for finding path or availability of other binaries. I understand that which can search for binaries (commands) which are present in the PATH variable set.
Now, I am unable to understand how to proceed in case the which command itself is not present on that machine.
My intention is to create a shell script (BASH) which can be run on a machine and in case the environment is not adequate (like some command being used in script is missing), it should be able to exit gracefully.
Does any one has any suggestions in this regard. I understand there can be ways like using locate or find etc - but again, what if even they are not available. Another option which I already know is that I look for existence of a which binary on standard path like /usr/bin/ or /bin/ or /usr/local/bin/. Is there any other possibility as well?
Thanks in advance.
type which
type is a bash built-in command, so it's always available in bash. See man bash for details on it.
Note, that this will also recognize aliases:
$ alias la='ls -l -a'
$ type la
la is aliased to 'ls -l -a'
(More of a comment because Boldewyn answered perfectly, but it is another take on the question that may be of interest to some.)
If you are worried that someone may have messed with your bash installation and somehow removed which, then I suppose in theory, when you actually invoked the command you would get an exit code of 127.
Consider
$ sdgsdg
-bash: sdgsdg: command not found
$ echo $?
127
Exit codes in bash: http://tldp.org/LDP/abs/html/exitcodes.html
Of course, if someone removed which, then I wouldn't trust the exit codes, either.