How can I escape a double quote inside double quotes?

Question

How can I escape double quotes inside a double string in Bash?

For example, in my shell script

#!/bin/bash

dbload=\"load data local infile \\\"\'gfp         


        

Answer 1

Bash allows you to place strings adjacently, and they'll just end up being glued together.

So this:

$ echo "Hello"', world!'

produces

Hello, world!

The trick is to alternate between single and double-quoted strings as required. Unfortunately, it quickly gets very messy. For example:

$ echo "I like to use" '"double quotes"' "sometimes"

produces

I like to use "double quotes" sometimes

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In your example, I would do it something like this:

$ dbtable=example
$ dbload='load data local infile "'"'gfpoint.csv'"'" into '"table $dbtable FIELDS TERMINATED BY ',' ENCLOSED BY '"'"'"' LINES "'TERMINATED BY "'"'\n'"'" IGNORE 1 LINES'
$ echo $dbload

which produces the following output:

load data local infile "'gfpoint.csv'" into table example FIELDS TERMINATED BY ',' ENCLOSED BY '"' LINES TERMINATED BY "'\n'" IGNORE 1 LINES

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It's difficult to see what's going on here, but I can annotate it using Unicode quotes. The following won't work in bash – it's just for illustration:

dbload=‘load data local infile "’“'gfpoint.csv'”‘" into’“table $dbtable FIELDS TERMINATED BY ',' ENCLOSED BY '”‘"’“' LINES”‘TERMINATED BY "’“'\n'”‘" IGNORE 1 LINES’

The quotes like “ ‘ ’ ” in the above will be interpreted by bash. The quotes like " ' will end up in the resulting variable.

If I give the same treatment to the earlier example, it looks like this:

$ echo“I like to use”‘"double quotes"’“sometimes”