Linux Shell Script - AWK usage

Title: Linux Shell Script - AWK usage 

Responsibility: Absolutely no responsibility. Use at your own risk.

awk '1' dbv_*.err  > alldf_mylog.txt

grep -E -w 'DBVERIFY - Verification starting|Total Pages Encrypted' alldf_mylog.txt >>  dbv_enc_apply_status.txt

sed 'N;s/\n/ /' dbv_enc_apply_status.txt > mergeeachDBFin1Line.txt

grep -E -w 'Total Pages Encrypted        : 0' mergeeachDBFin1Line.txt >>  onlyzero.txt

--

----grep -Ril "DBVERIFY - Verification starting : FILE = /oradata3/fcubs/PROD_mds.dbf"

grep 'warning\|error\|critical' /var/log/messages

awk 'NR % 6'            # prints all lines except lines 6,12,18...

awk 'NR > 5'            # prints from line 6 onwards (like tail -n +6, or sed '1,5d')

awk '$2 == "foo"'       # prints lines where the second field is "foo"

awk 'NF >= 6'           # prints lines with 6 or more fields

awk '/foo/ && /bar/'    # prints lines that match /foo/ and /bar/, in any order

awk '/foo/ && !/bar/'   # prints lines that match /foo/ but not /bar/

awk '/foo/ || /bar/'    # prints lines that match /foo/ or /bar/ (like grep -e 'foo' -e 'bar')

awk '/foo/,/bar/'       # prints from line matching /foo/ to line matching /bar/, inclusive

awk 'NF'                # prints only nonempty lines (or: do not print empty lines, where NF==0)

awk 'NF--'              # removes last field and prints the line

awk '$0 = NR" "$0'      # prepends line numbers (assignments are valid in conditions)

awk '!a[$0]++'          # suppresses duplicated lines! (figure out how it works)

[oracle@mysqldbwr1 tde1]$ more xyz.txt

1, Bakht

2, Hayat

3, Hasan Khalil

4, None

=====================================

--print only  second field where data is None" 

awk '$2 =="None"' xyz.txt

--print all records

[oracle@mysqldbwr1 tde1]$ awk '$2 =="None"' xyz.txt

4, None

awk '$1 $2' xyz.txt   ???

=====================================

--print all records

awk '$0' xyz.txt

[oracle@mysqldbwr1 tde1]$ awk '$0' xyz.txt

1, Bakht

2, Hayat

3, Hasan Khalil

4, None

=====================================

--print all records

awk '/Hayat/ || /Hasan/' xyz.txt

[oracle@mysqldbwr1 tde1]$ awk '/Hayat/ || /Hasan/' xyz.txt

2, Hayat

3, Hasan Khalil

=====================================

removes last field and prints the line

awk 'NF--' xyz.txt

1,

2,

3, Hasan

4,