i am new to shell scripting, i am trying to backup a file "main.sh" to "main.sh.bak" using a shell script. If the file exists perform the copy, else display a message. below is the script i am trying, i need to help in the "if" condition to check if the file exists or not in the current directory.
#!/bin/bash
echo "enter the file name"
read FILE
if [ -f $FILE ]; then
cp $FILE $FILE.bak
echo "file successfully backed up"
else
echo "file does not exists"
exit 1
fi
exit 0
The test command ([ xxx ] is the same as test xxx) for an existing regular file looks like:
if [ -f $FILE ]; then
<do something>
else
<do something>
fi
Important note: -f is for regular files, that is, for instance, not symbolic links or directories. So, if your files can be something else than regular files, type man test to know more about all test options and adapt to your specific case.
You can check if is a file exists with this sentence:
if [ -e $ FILE ]
Usign condition with [ ] are the same than command test there are more options to checks files, for instance:
-b FILE
FILE exists and is block special
-d FILE
FILE exists and is a directory
-f FILE
FILE exists and is a regular file
And much more, please execute man test to see all options
There is also an error in your script. You are missing an semicolon after the if statement.
So
if [ $FILE ] then
Should become:
if [ $FILE ]; then
echo -n "enter file name : "
read file
if [ -e $path/main.sh ]; then
cp /path/main.sh /path/main.bak
echo "Successfully back up"
else
echo "failed"
fi
exit 0;
test(or[) manual page.