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I need to replace Unix path via sed with variable that contain another unix path in a bash script

Example:

another_unix_path=/another/unix/path
sed -i 's/ \/some\/path\/file.txt/ '$another_unix_path'/g' some_file.txt
alphamikevictor
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vasek
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  • What work have you done on this so far? Please provide examples you've tried, and how they didn't end up working for you. – EEAA May 20 '15 at 11:55
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    Duplicate of [Stack Overflow question](http://stackoverflow.com/questions/407523/escape-a-string-for-a-sed-replace-pattern). – l0b0 May 20 '15 at 12:00

3 Answers3

3

Escaping special char / is an option.

You can also change the default sed separator (which is /) by using ? for example :

another_unix_path="/another/unix/path"
echo /some/path/file.txt | sed -e 's?/some/path/file.txt?'$another_unix_path'?g'

The char used just after the s flag defines which separator will be used : s?

Edit :

#!/bin/sh
basepath=/another/unix/path
baseurl=/base/url
sed -i 's?# set $IMAGE_ROOT /var/www/magento2;? set $IMAGE_ROOT '$basepath$baseurl';?g' somefile.txt
krisFR
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1

If you use / for separators, then you'll have to escape every / in your path, ex sed 's/\/some\/path/'$replacement'/g'

Fortunately sed - like Perl - allows many characters to be used as separators, so you can also write sed 's#/some/path#'$replacement'#g' (the g flag is used to allow replacing multiple occurrences per line).

Also sed will not allow in-place replacement if you run it on a file, meaning you will have to write to a temp file and move it over. Update: actually, Gnu's sed does have an in-place option which work like Perl's: -i or -i.ext where .ext is the backup extension. Perl may be preferable for portability though.

For in-place replacement you can use Perl as such:

# In-place without backup:
perl -pi -e 's#/some/path#'$replacement'#g' <file>

# In-place with backup as .orig (note .orig is glued to the -i switch):
perl -pi.orig -e 's#/some/path#'$replacement'#g' <file>

Be careful with the 2nd command, as if you enter it twice you will overwrite your first backup!

Thomas Guyot-Sionnest
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-1

You need to escape special characters:

another_unix_path="\/another\/unix\/path"
echo /some/path/file.txt | sed -e 's/\/some\/path\/file.txt/'$another_unix_path'/g'

Which outputs this result:

/another/unix/path

alphamikevictor
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