Bug 1293690 - Misbehavior when regexp isn't defined
Misbehavior when regexp isn't defined
Product: Fedora
Classification: Fedora
Component: sed (Show other bugs)
Unspecified Unspecified
unspecified Severity unspecified
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Assigned To: pstodulk
Fedora Extras Quality Assurance
Depends On:
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Reported: 2015-12-22 12:17 EST by Jakub Prokes
Modified: 2016-03-24 18:32 EDT (History)
4 users (show)

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Doc Type: Bug Fix
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Last Closed: 2016-03-24 18:32:28 EDT
Type: Bug
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Description Jakub Prokes 2015-12-22 12:17:57 EST
Description of problem:
When in replace command (s) isn't defined and address is defined by regexp, then sed use address regexp for replacing.

Version-Release number of selected component (if applicable):
sed (GNU sed) 4.2.2

How reproducible:
echo -e "foo\nbar" | sed '/o/s//X/'

Actual results:

Expected results:
sed: -e expression #1, char 0: no previous regular expression

Additional info:
[jprokes@patejl Wallpapers ]$ echo -e "foo\nbar" | sed '/o/s//X/'
[jprokes@patejl Wallpapers ]$ echo -e "foo\nbar" | sed '1s//X/'
sed: -e expression #1, char 0: no previous regular expression

When I compare these two commands, its behavior is inconsistent and possibly dangerous, in cases when sed is used inside larger bash script.
Comment 1 Paolo Bonzini 2016-03-24 18:32:28 EDT
// is defined to be the last regular expression that was used by the script.  In the case of /o/s//X/, the last regular expression to be tried before executing s//X/ was the address.

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