I am trying to learn the basics of shell. I used vim editro for creating my own list of commands to be executed. Here is the way I created the code
vi mycommands
then inside this file I wrote
cd Documents
I am using macOS Catalina which has zsh by default but switched to bash
So when I write the following command in the terminal:
$ sh +x mycommands
It shows
+cd Documents
The Documents has some files and directories but it is not changing directory.Where am I going wrong?
Any help will be greatly appreciated.
Scripts run like sh myscript execute in a separate sub-shell, not the current shell. Changing directory inside a script will not cause your shell to change directory. If you want to change directory in your shell, you need to run the commands in your shell.
To do that, run:
. ./myscript (sh, bash) or source ./myscript (bash).
See this question.
I try to run a gmt-script and get the message:
bash-3.2$ plot_scenario.gmt
bash: plot_scenario.gmt: command not found
Does anyone know what could fix the problem?
I got a script from my supervisor, and it worked just fine on the uni Linux pc.
I have a Mac OS.
When you type text in shell, it tries to look for available commands. Here bash doesn't find any command like plot_scenario.gmt and outputs command not found.
The proper way to execute a file is ./filename where . refers to current directory. But you need to give execution permission to file you want to run. So, following commands may help you:
chmod +x <filename>
./<filename>
Note that make sure your pwd is where you're file is located. Another way to run or execute file is calling the shell:
bash /path/to/file
I have in my $PATH my own path to my scripts.
I do that adding on my .bashrc
PATH=$PATH:~/home/user/myownscripts
In that directory I have two scripts, but only can use one of them, the first one I did create. And if created another script doesn't work neither.
Only can call the first script created.
The ls command return the following output
first_script second_script third_script
And first_script is bold and green
Why? and how fix this problem?
The second and third scripts are not executable. Use ls -l (provides more details about the files) to see the permissions of the files and run the following command to make these scripts executable.
chmod +x second_script third_script
If you run ls -l again, you should notice that they now have the x bit set in their file permissions.
This is a basic and fundamental aspect to Unix systems and I’d suggest that you read a book or tutorial on shell programming on a Unix-like system.
I'm trying to run source /Users/alastair/.rvm/scripts/rvm, but keep getting:
Bad : modifier in $ (").
Where would the problem be? Happy to paste other files in if these would help.
Are you in any case running a shell that is not Bash or ZSH? Bash >= 3.2.25 or ZSH >= 4.3.10 is required.
Your problem looks like you were using minimalistic shell sh which is not supported by RVM.
You can check user shell in /etc/passwd and change it with chsh -s /path/to/new/shell - list of allowed shells is available in /etc/shells - but make sure to pick Bash/ZSH, also note that links like sh->bash will not work as bash changes behavior based on the name that was invoked.
I am new to programming and am trying to follow an example which uses #! comment in ruby.
I am consistently get the message:
bash: matz.rb: command not found
I am using this comment:
#! /usr/bin/env ruby
I have tried it with and without the space after ! as well as with and without the env.
when I use the
$ which ruby
ruby is in: /usr/bin/ruby
I have also gone into the operating system and changed the permissions on the file matz.rb to rwx for all users w/ no effect. Am I doing something wrong or do I have my system set up incorrectly?
The /usr/bin/env part is fine. You need to give bash the path to matz.rb when you run it. If you're in the directory with matz.rb, type "./matz.rb". The directory "." means the current directory - bash doesn't look there by default when running programs (like Windows does).
The env program (/usr/bin/env) searches the executable search path - the PATH environment variable - for the ruby program as if you typed it at the command prompt, and runs that program. The shebang comment doesn't do this. If you want to give your script to other people who might not have ruby installed in the same place as you, then you should use the "#!/usr/bin/env ruby" comment so that it will work as long as they can run ruby by typing "ruby".
If you're in the same directory as the matz.rb file, be sure to run it as
$ ./matz.rb
and not just
$ matz.rb
Here's a shell session demonstrating this working:
$ ls -la m*
-rwxr-xr-x 1 gareth gareth 32 8 Jan 08:46 matz.rb
$ cat matz.rb
#!/usr/bin/env ruby
puts "Matz"
$ matz.rb
-bash: matz.rb: command not found
$ ./matz.rb
Matz
Your file wasn't created on Windows was it? If it has \r\n line endings, that will upset bash. You can open it with Vim and check:
vi matz.rb
:set ff=unix
:wq
If when you tab-complete the "ff=" part it says dos, then it has the wrong file format. Alternatively, run dos2unix and try to run the file again:
apt-get install sysutils
dos2unix matz.rb
It sounds like you're on a Unix/Linux system and just typing matz.rb on the command line. If you're trying to execute a command in the current directory, you need to call it like ./matz.rb. The "./" tells it to look in the current directory rather than just /usr/bin and friends.
I failed to see any answer indicating you to change the executable mode of the file, so you might wanna try and do
chmod +x matz.rb
before you go and try doing
./matz.rb
Also it might be better not to attach a .rb extension to the file, such is the case for normal ruby / rails scripts e.g. script/generate, script/console etc.
You can use the 'shebang' line with either:
#!/usr/bin/ruby
#!/usr/bin/env ruby
But the script needs to be executable (you indicated it is) and in your shell $PATH.
echo $PATH
Put the script in one of those directories, or modify your path, otherwise specify the full path to it, for example:
export PATH=$PATH:/home/user/bin
or one of these:
./matz.rb
/home/user/bin/matz.rb
You can also run the Ruby interpreter passing the script filename as an argument, and it will be executed. This is particularly useful if you have another version of Ruby installed on your system (say, for testing, like Ruby Enterprise Edition, REE):
/usr/bin/ruby matz.rb
/opt/ree/bin/ruby matz.rb
Have you tried the ShaBang as following to directly point to ruby?
#! /usr/bin/ruby
Then you call the script from the commandline as
./matz.rb
Under Unix/Linux systems the dot in front of a command to search for the command in the current directory. If you give a path like /usr/bin/ruby, it will search in the current directory for a directory called usr...
A command without a dot/ in front is searched in locations specified by the path variable of the environment.
A command with a / on the beginning is searched exactly from root following the specified path.
Inside your ShaBang, you want to specify the exact path to the interpreter so "/usr/bin/ruby" is the correct one. On the commandline, where you want your script to be executed, you need to call the script with "./matz.rb" otherwise the bash will search a command like /usr/bin/matz.rb what leads to your errormessage.