1 not defined in the RE?
My code goes like this:
cat file.ign | sed 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
Yet I receive an error saying :
sed: 1: "s/^([^A-Za-z0-9]+ )/<ig ...": 1 not defined in the RE
For the life of me, I cannot figure out my misdoing. If you need any extra information for helping me, let me know and I will reply.
sed
edited 3 hours ago
Jeff Schaller
40.9k1056130
asked 3 hours ago
Laura Laura
111
New contributor
Laura is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
My code goes like this:
cat file.ign | sed 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
Yet I receive an error saying :
sed: 1: "s/^([^A-Za-z0-9]+ )/<ig ...": 1 not defined in the RE
For the life of me, I cannot figure out my misdoing. If you need any extra information for helping me, let me know and I will reply.
sed
edited 3 hours ago
Jeff Schaller
40.9k1056130
asked 3 hours ago
Laura Laura
111
New contributor
Laura is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
My code goes like this:
cat file.ign | sed 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
Yet I receive an error saying :
sed: 1: "s/^([^A-Za-z0-9]+ )/<ig ...": 1 not defined in the RE
For the life of me, I cannot figure out my misdoing. If you need any extra information for helping me, let me know and I will reply.
sed
edited 3 hours ago
Jeff Schaller
40.9k1056130
asked 3 hours ago
Laura Laura
111
New contributor
Laura is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
My code goes like this:
cat file.ign | sed 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
Yet I receive an error saying :
sed: 1: "s/^([^A-Za-z0-9]+ )/<ig ...": 1 not defined in the RE
For the life of me, I cannot figure out my misdoing. If you need any extra information for helping me, let me know and I will reply.
sed
sed
edited 3 hours ago
Jeff Schaller
40.9k1056130
asked 3 hours ago
Laura Laura
111
New contributor
Laura is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 3 hours ago
Jeff Schaller
40.9k1056130
asked 3 hours ago
Laura Laura
111
New contributor
Laura is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 3 hours ago
Jeff Schaller
40.9k1056130
edited 3 hours ago
Jeff Schaller
40.9k1056130
edited 3 hours ago
Jeff Schaller
40.9k1056130
40.9k1056130
asked 3 hours ago
Laura Laura
111
New contributor
Laura is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 hours ago
Laura Laura
111
asked 3 hours ago
Laura Laura
111
111
New contributor
Laura is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Laura is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Laura is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
add a comment |
1 Answer
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Parentheses are literal in basic regular expression (BRE) syntax - to make them denote a capture group, they must be escaped, as ( and )
Additionally, as noted in a comment by @BenjaminW, + is also literal in BRE. GNU sed supports + as a quantifier in BRE:
sed 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
(but other implementations might not). Alternatively, turn on extended regular expression (ERE) mode using the -E or -r command line switch as appropriate (check your version's documentation):
sed -E 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
or use the POSIX-compliant quantifier {1,}
sed 's/^([^A-Za-z0-9]{1,} )/<ignore>1</ignore>/g'
ASIDE the g (global replacement) modifier won't have any effect here, since ^ anchors the expression to the start of the pattern (which can occur only once per line)
answered 3 hours ago
steeldriversteeldriver
36k35286
1
Furthermore,+is only avalable in ERE; GNU sed supports it as an extension in BRE, but is has to be escaped.
– Benjamin W.
2 hours ago
@BenjaminW. oops yes that's a good point - I missed that
– steeldriver
2 hours ago
The-Ealso is GNU or FreeBSD sed, not in POSIX. If you're going to recommend a non-POSIX solution, mentioning that might help the reader.
– Thomas Dickey
1 hour ago
add a comment |
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1 Answer
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1 Answer
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votes
Parentheses are literal in basic regular expression (BRE) syntax - to make them denote a capture group, they must be escaped, as ( and )
Additionally, as noted in a comment by @BenjaminW, + is also literal in BRE. GNU sed supports + as a quantifier in BRE:
sed 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
(but other implementations might not). Alternatively, turn on extended regular expression (ERE) mode using the -E or -r command line switch as appropriate (check your version's documentation):
sed -E 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
or use the POSIX-compliant quantifier {1,}
sed 's/^([^A-Za-z0-9]{1,} )/<ignore>1</ignore>/g'
ASIDE the g (global replacement) modifier won't have any effect here, since ^ anchors the expression to the start of the pattern (which can occur only once per line)
answered 3 hours ago
steeldriversteeldriver
36k35286
1
Furthermore,+is only avalable in ERE; GNU sed supports it as an extension in BRE, but is has to be escaped.
– Benjamin W.
2 hours ago
@BenjaminW. oops yes that's a good point - I missed that
– steeldriver
2 hours ago
The-Ealso is GNU or FreeBSD sed, not in POSIX. If you're going to recommend a non-POSIX solution, mentioning that might help the reader.
– Thomas Dickey
1 hour ago
add a comment |
Parentheses are literal in basic regular expression (BRE) syntax - to make them denote a capture group, they must be escaped, as ( and )
Additionally, as noted in a comment by @BenjaminW, + is also literal in BRE. GNU sed supports + as a quantifier in BRE:
sed 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
(but other implementations might not). Alternatively, turn on extended regular expression (ERE) mode using the -E or -r command line switch as appropriate (check your version's documentation):
sed -E 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
or use the POSIX-compliant quantifier {1,}
sed 's/^([^A-Za-z0-9]{1,} )/<ignore>1</ignore>/g'
ASIDE the g (global replacement) modifier won't have any effect here, since ^ anchors the expression to the start of the pattern (which can occur only once per line)
answered 3 hours ago
steeldriversteeldriver
36k35286
1
Furthermore,+is only avalable in ERE; GNU sed supports it as an extension in BRE, but is has to be escaped.
– Benjamin W.
2 hours ago
@BenjaminW. oops yes that's a good point - I missed that
– steeldriver
2 hours ago
The-Ealso is GNU or FreeBSD sed, not in POSIX. If you're going to recommend a non-POSIX solution, mentioning that might help the reader.
– Thomas Dickey
1 hour ago
add a comment |
Parentheses are literal in basic regular expression (BRE) syntax - to make them denote a capture group, they must be escaped, as ( and )
Additionally, as noted in a comment by @BenjaminW, + is also literal in BRE. GNU sed supports + as a quantifier in BRE:
sed 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
(but other implementations might not). Alternatively, turn on extended regular expression (ERE) mode using the -E or -r command line switch as appropriate (check your version's documentation):
sed -E 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
or use the POSIX-compliant quantifier {1,}
sed 's/^([^A-Za-z0-9]{1,} )/<ignore>1</ignore>/g'
ASIDE the g (global replacement) modifier won't have any effect here, since ^ anchors the expression to the start of the pattern (which can occur only once per line)
answered 3 hours ago
steeldriversteeldriver
36k35286
Parentheses are literal in basic regular expression (BRE) syntax - to make them denote a capture group, they must be escaped, as ( and )
Additionally, as noted in a comment by @BenjaminW, + is also literal in BRE. GNU sed supports + as a quantifier in BRE:
sed 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
(but other implementations might not). Alternatively, turn on extended regular expression (ERE) mode using the -E or -r command line switch as appropriate (check your version's documentation):
sed -E 's/^([^A-Za-z0-9]+ )/<ignore>1</ignore>/g'
or use the POSIX-compliant quantifier {1,}
sed 's/^([^A-Za-z0-9]{1,} )/<ignore>1</ignore>/g'
ASIDE the g (global replacement) modifier won't have any effect here, since ^ anchors the expression to the start of the pattern (which can occur only once per line)
answered 3 hours ago
steeldriversteeldriver
36k35286
edited 59 mins ago
answered 3 hours ago
steeldriversteeldriver
36k35286
answered 3 hours ago
steeldriversteeldriver
36k35286
answered 3 hours ago
steeldriversteeldriver
36k35286
36k35286
1
Furthermore,+is only avalable in ERE; GNU sed supports it as an extension in BRE, but is has to be escaped.
– Benjamin W.
2 hours ago
@BenjaminW. oops yes that's a good point - I missed that
– steeldriver
2 hours ago
The-Ealso is GNU or FreeBSD sed, not in POSIX. If you're going to recommend a non-POSIX solution, mentioning that might help the reader.
– Thomas Dickey
1 hour ago
add a comment |
1
Furthermore,+is only avalable in ERE; GNU sed supports it as an extension in BRE, but is has to be escaped.
– Benjamin W.
2 hours ago
@BenjaminW. oops yes that's a good point - I missed that
– steeldriver
2 hours ago
The-Ealso is GNU or FreeBSD sed, not in POSIX. If you're going to recommend a non-POSIX solution, mentioning that might help the reader.
– Thomas Dickey
1 hour ago
1
1
Furthermore,
+ is only avalable in ERE; GNU sed supports it as an extension in BRE, but is has to be escaped.– Benjamin W.
2 hours ago
Furthermore,
+ is only avalable in ERE; GNU sed supports it as an extension in BRE, but is has to be escaped.– Benjamin W.
2 hours ago
@BenjaminW. oops yes that's a good point - I missed that
– steeldriver
2 hours ago
@BenjaminW. oops yes that's a good point - I missed that
– steeldriver
2 hours ago
The
-E also is GNU or FreeBSD sed, not in POSIX. If you're going to recommend a non-POSIX solution, mentioning that might help the reader.– Thomas Dickey
1 hour ago
The
-E also is GNU or FreeBSD sed, not in POSIX. If you're going to recommend a non-POSIX solution, mentioning that might help the reader.– Thomas Dickey
1 hour ago
add a comment |
Laura is a new contributor. Be nice, and check out our Code of Conduct.
Laura is a new contributor. Be nice, and check out our Code of Conduct.
Laura is a new contributor. Be nice, and check out our Code of Conduct.
Laura is a new contributor. Be nice, and check out our Code of Conduct.
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