Passing SED replace arguments within a BASH variable

Question

I'm trying to pass a variable with spaces in it to sed using BASH, and in the prompt, it works fine:

$ tmp=/folder1/This Folder Here/randomfile.abc
$ echo "$tmp" | sed -e 's/ /\\ /g'
/folder1/This\ Folder\ Here/randomfile.abc

But as soon as I pass it to a variable, sed no longer replaces the space with a backslash:

$ tmp=/folder1/This Folder Here/randomfile.abc
$ location=`echo "$tmp" | sed -e 's/ /\\ /g'`
$ echo $location
/folder1/This Folder Here/randomfile.abc

I'm hoping a second pair of eyes can pick up on something that I'm not.

As per the first example, I want to add a backslash to all spaces within the variable, so 'This Folder Here', would be 'This\ Folder\ Here'. — hobbes
– hobbes, Commented Apr 16, 2014 at 19:44
Yes that I can see but why do you want to escape every space? — anubhava
– anubhava, Commented Apr 16, 2014 at 19:46

devnull · Accepted Answer · 2014-04-17 01:57:43Z

5

You need a couple of pairs of backslashes:

sed -e 's/ /\\\\ /g'

You seem to want to quote the input so as to use it as shell input. There is no need to use sed. You could use printf:

$ foo="a string with spaces"
$ printf "%q" "$foo"
a\ string\ with\ spaces

edited Apr 17, 2014 at 1:57

answered Apr 16, 2014 at 19:45

devnull

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hobbes Over a year ago

That did it! I'd vote up if I had the reputation. Thanks devnull.

Kevin · Accepted Answer · 2014-04-16 19:47:52Z

3

The quotes are being evaluated by bash during the assignment. You can get around this by quoting:

location="$(echo "$tmp" | sed -e 's/ /\\ /g')"

or devnull's answer (double the quotes)

Or switch to zsh to make things like this easier

% echo $tmp
/folder1/This Folder Here/randomfile.abc
% echo ${(q)tmp}
/folder1/This\ Folder\ Here/randomfile.abc

answered Apr 16, 2014 at 19:47

Kevin

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hobbes Over a year ago

This also works, I derped by not using '"$('. Thanks for the update!

Sir Athos · Accepted Answer · 2014-04-16 19:57:07Z

3

You need to use more quoting.

tmp="/folder1/This Folder Here/randomfile.abc"
location="$(echo "$tmp" | sed -e 's/ /\\ /g')"
echo "$location"

There's also a pure bash solution to insert the backslashes:

tmp="/folder1/This Folder Here/randomfile.abc"
echo "${tmp// /\\ }"

edited Apr 16, 2014 at 19:57

answered Apr 16, 2014 at 19:47

Sir Athos

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