How do I create a script file for terminal commands?

Question

In Windows I can write a file containing commands for cmd (usually .cmd or .bat files). When I click on those files it will open cmd.exe and run them commands the file contains.

How would I do this in Ubuntu?

I'm sure this is a duplicate, but I can't find my answer.
Its similar to these questions, but they don't answer the question:

Store frequently used terminal commands in a file

CMD.exe Emulator in Ubuntu to run .cmd/.bat file

Answer 1

There are two methods.

First, the most common is to write a file, make sure the first line is

#!/bin/bash

Then save the file. Next mark it executable using chmod +x file

Then when you click (or run the file from the terminal) the commands will be executed. By convention these files usually have no extension, however you can make them end in .sh or any other way.

A few notes:

• Any (and I mean any) file can be executed in Linux provided the first line is a path to the program that should interpret the file. Common examples include /bin/python, /bin/sh, /bin/dash, but even odd ball things work like /bin/mysql
• Bash is a full language. It is vastly more complex than cmd.exe in windows. It has a strong programming language that supports functions, loops, conditionals, string operations, etc.
• These documents may help if you run into problems.
• If you do not wish to make the file executable then you can run it by passing it as an argument to bash: bash file/to/run.sh

A Simple Bash Example

#!/bin/bash  
echo "This is a shell script"  
ls -lah  
echo "I am done running ls"  
SOMEVAR='text stuff'  
echo "$SOMEVAR"

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The second method is to record commands using script. Run script then just do stuff. When you are done doing stuff type exit and script will generate a file for you with all the "stuff" you did. This is less used but works quite well for making things like macros. man script for more info.

Answer 2

You mean writing to a file using a shell script? Here are a few ways:

touch file

This method will simply create a file, but if the file already exists, it simply changes the modification date to the time you used that command.

echo "text" > file

That method overwrites the contents of file to text. If you wanted to clear a file, you can simply do this:

echo "" > file

Say you want to write more than one line to it, and you don't want to use thousands of echo commands, you would use this command:

cat << EOF > file
test
test1
foo
bar
EOF

That enables you to write multiple lines in one command. The contents of file would then be this:

test
test1
foo
bar

If you wanted to append to a file, replace > to >>.

Hope this helps!

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EDIT: Oh, I see, so you would write the file in gedit, using the .sh extension (optional, but it's a good idea), and then on a file manager, right click on the file, select Properties->Permissions, and check Allow executing file as program. Then you can double-click on it and it will run :). Also, if you want to do so in the terminal, you can run this command to make it executable (you might want to prepend sudo if it doesn't belong to you):

chmod +x file

And to run:

./file

Answer 3

The equivalent to Windows batch files is shell scripts, and an excellent getting started guide is Bash Scripting.

For the most part, commands that you can enter on the command line can be placed in a shell script.

A couple of things that are different from Windows batch files:

• There are different command interpretors, called shells. The default is bash, but if you are interested, there are others, such as zsh, ksh, dash, perl, python, etc.

• To run a shell script, you need to make the file executable, which you can do with chmod +x <filename>

• In Ubuntu, the current directory is not the program search path, so you need to run ./<filename>, not <filename>

• Variable names are $<varname>, not %<varname>%

• Commands in a shell script are not printed by default, as in a batch file.

• The filename's extension can be .sh or (more customary) you don't need to use an extension. Put #!/bin/bash on the very first line of the file, which tells Ubuntu what program to use to run the file.

• Comments start with #, not rem.

Hope this helps and have fun scripting!