Shell Commands : awk

Basic Uses

$ cat score.txt
Group   Name    English Math    History Science
A       Mina    82      67      93      98
A       Joan    66      45      59      30
B       Kevin   95      100     91      100
B       Noa     92      99      95      97
A       Tom     83      80      74      88
B       David   83      69      99      65


$ awk /A/ score.txt
A       Mina    82      67      93      98
A       Joan    66      45      59      30
A       Tom     83      80      74      88

$ awk '$2 - /Tom/' score.txt
A       Tom     83      80      74      88

$ awk '$1 - !/A/' score.txt
Group   Name    English Math    History Science
B       Kevin   95      100     91      100
B       Noa     92      99      95      97
B       David   83      69      99      65

$ awk '$1 == "A" {print $0}' score.txt
A       Mina    82      67      93      98
A       Joan    66      45      59      30
A       Tom     83      80      74      88

$ awk '{if($1 == "B") print $0}' score.txt
B       Kevin   95      100     91      100
B       Noa     92      99      95      97
B       David   83      69      99      65

$ awk '{print $2}' score.txt
Name
Mina
Joan
Kevin
Noa
Tom
David

$ awk '{print $3, $4, $3+$4}' score.txt
English Math 0
82 67 149
66 45 111
95 100 195
92 99 191
83 80 163
83 69 152

$ awk '{s = $3+$4; print $0, s}' score.txt
Group   Name    English Math    History Science 0
A       Mina    82      67      93      98 149
A       Joan    66      45      59      30 111
B       Kevin   95      100     91      100 195
B       Noa     92      99      95      97 191
A       Tom     83      80      74      88 163
B       David   83      69      99      65 152

Useing File

$ cat add
{sum = $3 + $4 + $5 + $6; print $0, sum}

$ awk -f add score.txt
Group   Name    English Math    History Science 0
A       Mina    82      67      93      98 340
A       Joan    66      45      59      30 200
B       Kevin   95      100     91      100 386
B       Noa     92      99      95      97 383
A       Tom     83      80      74      88 325
B       David   83      69      99      65 316

BEGIN and END

$ cat GradeA
BEGIN {
        print "----------------------------"
        print "Students List with Grade A"
        print "----------------------------"
}
{
        mean = ($3 + $4 + $5 + $6) / 4
        if (mean > 90) {print $2, "Average is", mean}
}
END {
        print "----------------------------"
}

$ awk -f GradeA score.txt
----------------------------
Students List with Grade A
----------------------------
Kevin Average is 96.5
Noa Average is 95.75
----------------------------

Field Separator

$ cat s.txt
Group:Name:English:Math:History:Science
A:Mina:82:67:93:98
A:Joan:66:45:59:30
B:Kevin:95:100:91:100
B:Noa:92:99:95:97
A:Tom:83:80:74:88
B:David:83:69:99:65

$ awk -F: '{print $2}' s.txt
Name
Mina
Joan
Kevin
Noa
Tom
David

$ awk -F: -f GradeA s.txt
----------------------------
Students List with Grade A
----------------------------
Kevin Average is 96.5
Noa Average is 95.75
----------------------------

reference

• http://blog.naver.com/teastful/140125891562