Double Quote To Prevent Globbing And Word Splitting
Are you tired of seeing your commands fail because of globbing and word splitting? These issues can make it difficult to execute commands properly and can lead to unexpected results. Fortunately, there is a simple solution that can help prevent these problems – using double quotes.
What is Globbing and Word Splitting?
Globbing is the process of expanding wildcard characters such as * and ? in a command. For example, if you run the command ls *.txt, the shell will expand the * character to match all files with a .txt extension in the current directory.
Word splitting occurs when the shell breaks up a command into separate words based on spaces or other delimiters. For example, if you run the command echo hello world, the shell will break it up into two separate words – "hello" and "world".
These processes can cause issues when you want to pass a string containing wildcard characters or spaces as a single argument to a command. The shell will interpret the string as separate arguments, which can lead to unexpected results.
Using Double Quotes
To prevent globbing and word splitting, you can use double quotes around your strings. When you enclose a string in double quotes, the shell will treat it as a single argument, regardless of any spaces or wildcard characters it contains.
For example, instead of running the command ls *.txt, you could run the command ls "*.txt". The double quotes will prevent the shell from expanding the * character and treat it as a literal character instead.
Similarly, if you want to pass a string with spaces as a single argument, you can enclose it in double quotes as well. For example, instead of running the command echo hello world, you could run the command echo "hello world". The double quotes will prevent the shell from breaking up the string into separate words.
Escaping Double Quotes
If you need to include double quotes within a string that is already enclosed in double quotes, you can escape them using a backslash (\) character. For example, if you want to pass the string "hello "world" to a command, you can enclose it in double quotes and escape the inner double quotes like this: "hello \\"world\\"".
Conclusion
By using double quotes to prevent globbing and word splitting, you can ensure that your commands are executed properly and produce the expected results. Remember to also escape any double quotes within a string that is already enclosed in double quotes.