place a multi-line output inside a variable

问题

I'm writing a script in bash and I want it to execute a command and to handle each line separately. for example:

LINES=$(df)
echo $LINES

it will return all the output converting new lines with spaces.

example:

if the output was supposed to be:

1
2
3

then I would get

1 2 3

how can I place the output of a command into a variable allowing new lines to still be new lines so when I print the variable i will get proper output?

回答1:

Generally in bash $v is asking for trouble in most cases. Almost always what you really mean is "$v" in double quotes.

LINES="`df`"     # double-quote + backtick
echo "$LINES"
OLDPATH="$PATH"

回答2:

No, it will not. The $(something) only strips trailing newlines.

The expansion in argument to echo splits on whitespace and than echo concatenates separate arguments with space. To preserve the whitespace, you need to quote again:

echo "$LINES"

Note, that the assignment does not need to be quoted; result of expansion is not word-split in assignment to variable and in argument to case. But it can be quoted and it's easier to just learn to just always put the quotes in.

来源：https://stackoverflow.com/questions/8713158/place-a-multi-line-output-inside-a-variable