Shell中的Grep从特定字符串中提取一行

Question

I have a file with below text

^[[8mha:AAAAYB+LCAAAAAAAAP9b85aBtbiIQSmjNKU4P0+vJLE4u1gvPjexLDVPzxdEuhYV5Rf55ZekOlc7RKnPKH7IxMBQUcQgBdWQnJ9XnJ+TqucMoUEKGSCAEaSwAACsNFCqYAAAAA==^[[0m[ERROR] ^[[8mha:AAAAYB+LCAAAAAAAAP9b85aBtbiIQSmjNKU4P0+vJLE4u1gvPjexLDVPzxdEuhYV5Rf55ZekOlc7RKnPKH7IxMBQUcQgBdWQnJ9XnJ+TqucMoUEKGSCAEaSwAACsNFCqYAAAAA==^[[0m[ERROR] /opt/app/ElectronicTransactionVOtoDOMapper.java:[1060,1] error: reached end of file while parsing ^[[8mha:AAAAYB+LCAAAAAAAAP9b85aBtbiIQSmjNKU4P0+vJLE4u1gvPjexLDVPzxdEuhYV5Rf55ZekOlc7RKnPKH7IxMBQUcQgBdWQnJ9XnJ+TqucMoUEKGSCAEaSwAACsNFCqYAAAAA==^[[0m[ERROR] -> [Help 1] ^[[8mha:AAAAYB+LCAAAAAAAAP9b85aBtbiIQSmjNKU4P0+vJLE4u1gvPjexLDVPzxdEuhYV5Rf55ZekOlc7RKnPKH7IxMBQUcQgBdWQnJ9XnJ+TqucMoUEKGSCAEaSwAACsNFCqYAAAAA==^[[0m[ERROR] ^[[8mha:AAAAYB+LCAAAAAAAAP9b85aBtbiIQSmjNKU4P0+vJLE4u1gvPjexLDVPzxdEuhYV5Rf55ZekOlc7RKnPKH7IxMBQUcQgBdWQnJ9XnJ+TqucMoUEKGSCAEaSwAACsNFCqYAAAAA==^[[0m[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch

from the above log, I have to extract only the below:

[ERROR]
[ERROR] /opt/app/ElectronicTransactionVOtoDOMapper.java:[1060,1] error: reached end of file while parsing
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch

Eventually, I should not get the Junk value in the log instead I need a clear Error message.

Could you please help me in getting the right command in shell?

Answer 1

probably should use sed rather than grep here.

sed -n '/ERROR/s/.*\(\[ERROR\].*\)$/\1/p' log_10-29-2016_04_12

gets only lines containing the word 'ERROR' and strips everything from the left of the '[ERROR]' and prints the rest.

Answer 2

awk -vRS='^' -F "] " '/ERROR/{print "[ERROR] "$2}' file

Answer 3

Try below grep command to achieve the output -

vipin@kali:~$ grep "\[ERROR\]" kk.txt |cut -c6-
[ERROR]
[ERROR] /opt/app/ElectronicTransactionVOtoDOMapper.java:[1060,1] error: reached end of file while parsing
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch

explanation : \\[ and \\] for escaping and -c6- to print after 6th character till end of line.