BASH Script passing variable with space to Heredoc?

Question

I'm using the following:

filename="Test File 17-07-2020.xls"

sshpass -p $password ssh root@$IP /bin/bash -s "$filename" << 'EOF'

echo $1

EOF

This works when filename equals Testfile.xls and the echo outputs the full filename.

But fails if the filename is called Test File 17-07-2020.xls

My understanding is the spaces are breaking the input so it becomes:

$1 = Test
$2 = File
$3 = 17-07-2020.xls

Is there anyway to pass this keeping the spaces and having it all in $1

If I add filename=$(echo "$filename" | sed 's/ /\\ /g') before the SSHPASS command it does work.

Is that a valid way to do it or is there a better way ?

Thanks

As a poor substitute in cases where you don't need that second argument you could maybe use "$*" instead of $1, but it isn't a very robust solution. — Paul Hodges
– Paul Hodges, Commented Jul 13, 2020 at 17:50

chepner · Accepted Answer · 2020-07-13 13:20:12Z

1

You still need to quote $1. Quoting the delimiter prevents $1 from being expanded early; it doesn't prevent word splitting once the shell actually executes echo $1.

sshpass -p $password ssh root@$IP "/bin/bash -s \"$filename\"" << 'EOF'

echo "$1"

EOF

If you are using bash locally, there are two extensions that could produce a value that is safe to pass to the remote shell.

sshpass -p $password ssh root@$IP "/bin/bash -s $(printf '%q' "$filename")"

or

sshpass -p $password ssh root@$IP "/bin/bash -s ${filename@Q}"

The former works at least in bash 3.2 (I highly doubt you are using an older version), while the latter requires bash 4.4.

edited Jul 13, 2020 at 13:20

answered Jul 13, 2020 at 13:01

chepner

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5 Comments

Tom Over a year ago

I've found this, but if the filename has spaces without the slashes then $1 only contains Test.

chepner Over a year ago

Oh, right, because the entire set of arguments is packaged as a single word by ssh to pass to the remote shell. I've fixed it to handle your case, but this still isn't robust: it will fail if $filename contains a double-quote itself.

chepner Over a year ago

You could swap the inner double quotes for single quotes ("/bin/bash -s '$filename'"), but that just shifts the problem to filenames containing single quotes.

oguz ismail Over a year ago

How about ${filename@Q}?

chepner Over a year ago

Yeah, I was just playing around with that. printf '%q' "$filename" and "${filename@Q}" produce different output, so I was trying to convince myself either would work. (I might lean towards print "%q" ... as being more likely to be supported; @Q requires bash 4.4 or later.

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