Using different delimiters in sed commands and range addresses - sed

Question

I am using sed in a shell script to edit filesystem path names. Suppose I want to replace
/foo/bar
with
/baz/qux
However, sed's s/// command uses the forward slash / as the delimiter. If I do that, I see an error message emitted, like:
▶ sed 's//foo/bar//baz/qux//' FILE
sed: 1: "s//foo/bar//baz/qux//": bad flag in substitute command: 'b'
Similarly, sometimes I want to select line ranges, such as the lines between a pattern foo/bar and baz/qux. Again, I can't do this:
▶ sed '/foo/bar/,/baz/qux/d' FILE
sed: 1: "/foo/bar/,/baz/qux/d": undefined label 'ar/,/baz/qux/d'
What can I do?

Answer 1

You can use an alternative regex delimiter as a search pattern by backslashing it:
sed '\,some/path,d'
And just use it as is for the s command:
sed 's,some/path,other/path,'
You probably want to protect other metacharacters, though; this is a good place to use Perl and quotemeta, or equivalents in other scripting languages.
From man sed:
/regexp/
Match lines matching the regular expression regexp.
\cregexpc
Match lines matching the regular expression regexp. The c may be any character other than backslash or newline.
s/regular expression/replacement/flags
Substitute the replacement string for the first instance of the regular expression in the pattern space. Any character other than backslash or newline can be used instead of a slash to delimit the RE and the replacement. Within the RE and the replacement, the RE delimiter itself can be used as a literal character if it is preceded by a backslash.

Answer 2

Perhaps the closest to a standard, the POSIX/IEEE Open Group Base Specification says:
[2addr] s/BRE/replacement/flags
Substitute the replacement string for instances of the BRE in the
pattern space. Any character other than backslash or newline can
be used instead of a slash to delimit the BRE and the replacement.
Within the BRE and the replacement, the BRE delimiter itself can be
used as a literal character if it is preceded by a backslash."

Answer 3

When there is a slash / in theoriginal-string or the replacement-string, we need to escape it using \. The following command is work in ubuntu 16.04(sed 4.2.2).
sed 's/\/foo\/bar/\/baz\/qux/' file