create file shell script - linux

I am new to shell scripting in Linux and I am trying to take data from the keyboard and then append the data passed in to a file. Pretty straight forward but I am getting an error when I try to create the file. The error says "you do not have permission to create this file".
I first do a check to make sure the file exists. If it exists, append to the end of the file. If not, create the file. What am I doing wrong?
Thank you!
P.S. In this case, I do not have the file created yet
#!/bin/sh
echo "Please enter your first name";
read first
echo "Please enter your last name";
read last
combine=":$first $last"
file="/testFile.dat"
if [ -f "$file" ]
then
echo "$file found."
echo $combine >> $file
else
echo "$file not found. Will create the file and add entry now."
touch $file
$combine >> $file
fi


You're trying to write to the file /testFile.dat which is located in the root directory /. It is highly likely that as a regular user you would not have write permissions for creating such a file.
But what you wanted I'm guessing is to create the testfile.dat in the current directory.
Replace the following line:
file="/testFile.dat"
with:
file="./testFile.dat"


You are creating the file at the root. Try file="~/testFile.dat" to create the file in your home or just file="./testFile.dat" to create it in the current directory.

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I am trying to create a script in Linux that will prompt the user to input the name of a file and according to the user's input it will create the file and put the following in the file "This is a file (filename)."
This is my attempt so far.
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You're not redirecting the output of the script to the file, and you're not using $ to expand the variable. Change the last line of the script to:
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how to print the ouput/error to a text file?

I'm trying to redirect(?) my standard error/output to a text file.
I did my research, but for some reason the online answers are not working for me.
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cd /home/user1/lists/
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) > /root/Desktop/Logs/Update.log
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Help please!

Try this for the basics:
echo hello >> log.txt 2>&1
Could be read as: echo the word hello, redirecting and appending STDOUT to the file log.txt. STDERR (file descriptor 2) is redirected to wherever STDOUT is being pointed. Note that STDOUT is the default and thus there is no "1" in front of the ">>". Works on the current line only.
To redirect and append all output and error of all commands in a script, put this line near the top. It will be in effect for the length of the script instead of doing it on each line:
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If you are trying to obtain a list of the files in /home/user1/lists, you do not need a loop at all:
ls /home/usr1/lists/ >Update.log
If you are attempting to run every file in the directory as an executable with a newline as its input, and collect the output from all these programs in Update.log, try this:
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done
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done
In your original program, you redirect the echo inside the loop, which means that the redirection after done will not receive any output at all, so the created file will be empty.
These are somewhat wild guesses at what you might actually be trying to accomplish, but should hopefully help nudge you slightly in the right direction. (This should properly be a comment, I suppose, but it's way too long and complex.)

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