Should environment variables have quotes?
Quoting is mostly orthogonal. If the value you’re assigning to the variable doesn’t contain any characters that are special to the shell, you don’t need any quotes. If there are special characters, you need to protect them with single quotes or double quotes or backslashes or a combination thereof.
What is the purpose of a single quote character?
Single quotation marks are used to indicate quotations inside of other quotations. “Jessie said, ‘Goodbye,’” Ben said. This is Ben talking, so his words go in quotation marks. But because we’re quoting Ben quoting someone else, Jessie, we use single quotation marks to indicate the quote within the quote.
Can a single quote occur between two quotes?
A single quote may not occur between single quotes, even when preceded by a backslash. […] Enclosing characters in double quotes ( “) preserves the literal value of all characters within the quotes, with the exception of $, `, \\, and, when history expansion is enabled, !.
What’s the difference between single and double quotes in Bash?
In Bash, what are the differences between single quotes ( ”) and double quotes ( “” )? Single quotes won’t interpolate anything, but double quotes will. For example: variables, backticks, certain \\ escapes, etc. Enclosing characters in single quotes ( ‘) preserves the literal value of each character within the quotes.
When to enclose characters in double quotes?
Enclosing characters in double quotes (“) preserves the literal value of all characters within the quotes, with the exception of $, `, \\, and, when history expansion is enabled, !. The characters $and `retain their special meaning within double quotes (see Shell Expansions).
When to use double quotes in a string?
Double Quotes. Use when you want to enclose variables or use shell expansion inside a string. All characters within are interpreted as regular characters except for $ or ` which will be expanded on the shell.