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Curly braces in sed

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# 8  
Old 06-18-2015
Quote:
Originally Posted by tostay2003
Great.. This works... is ^ in square brackets used as a negation?
Exactly:

Code:
[AB]     # matches "A" or "B"
[^AB]    # matches any character except "A" or "B"

You need this quite often, because matches in sed are always "greedy". Suppose the following text:

Code:
AXXBABABABXABABABAB

the expression /A.*B/ will match the whole string, not just the first four characters! If several possiblities for a match exist always the longest possible one will be taken:
Code:
AXXBABABABXABABABAB
A<------ .* ----->B

If you want to match only up to the first "B" you need to:

Code:
AXXBABABABXABABABAB
A[^B]*B
AXXB

I hope this helps.

bakunin
Last edited by bakunin; 06-18-2015 at 11:23 AM..
This User Gave Thanks to bakunin For This Post:
tostay2003
# 9  
Old 06-24-2015
Hi,


Thanks for the detailed description.

I tried changing the below sed to fetch the first available numeric, but was unable to get the results.

Code:
echo "testing.123.xyz.456.txt" | sed -n 's/[^.]*\.\([0-9]\{1,\}\)\..*/\1/p'

Ideally, my code has to fetch any numeric value that comes first and matching a pattern.

Code:
Pattern -> testing.123.xyz.*.txt 
Actual Value -> testing.123.xyz.456.txt 
----> This should result in 123

If pattern DOES NOT have a * only first available value needs to be extracted
Code:
abc123testing456 ----> should result in 123
123abctesting456 ----> should result in 123

Any ideas how we can change the code to achieve the above result
Last edited by tostay2003; 06-24-2015 at 08:46 AM..
# 10  
Old 06-24-2015
Not quite sure what you mean by "above result". However, try
Code:
sed -rn 's/[^0-9]*([0-9]{1,})[^0-9]*.*/\1/p' file

This User Gave Thanks to RudiC For This Post:
tostay2003
# 11  
Old 06-24-2015
Quote:
Originally Posted by RudiC
Not quite sure what you mean by "above result". However, try
Code:
sed -rn 's/[^0-9]*([0-9]{1,})[^0-9]*.*/\1/p' file

In all the below cases (for eg.) the result should be "1234"
Code:
abc.1234.xyz.456.999
abc.1234testing456 
abc1234testing456 
1234abctesting456

Code:
Result :1234

I do not have system in front of me. I can check it tomorrow.

Does the above code which you have given return
Code:
"23"

. Please correct me If I am wrong whether the values 1 and 4 gets absorbed by
Code:
[^0-9]

# 12  
Old 06-24-2015
Result of sed script in post#10 applied to your last sample:
Code:
1234
1234
1234
1234

Last edited by RudiC; 06-25-2015 at 10:48 AM..
# 13  
Old 06-24-2015
Code:
$ cat numbers.file
abc.1234.xyz.456.999
abc.1234testing456 
nonumbershere
abc1234testing456 
voidofnumbers
1234abctesting456

$ perl -nle '/(\d+)/ and print $1' numbers.file 
1234
1234
1234
1234

# 14  
Old 06-25-2015
Regular sed:
Code:
sed -n 's/^[^0-9]*\([0-9]\{1,\}\).*/\1/p' file

GNU awk:
Code:
awk -v FPAT='[0-9]+' 'NF{print $1}' file

Regular awk:
Code:
awk 'match($0,/[0-9]+/){print substr($0,RSTART,RLENGTH)}' file

Last edited by Scrutinizer; 06-25-2015 at 10:17 AM..
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