awk Command Learning

It is said that some people use this outfit to force. Ha ha. I just have to master the basics.

awk ' Condition 1{action 1} Condition 2{action 2} ... ' Filename

Condition (Pattern):

-General use of relationship expressions as criteria

-You can use functions, etc.

Actions (Action):

-Formatted output

-Process Control Statements

Test Document:

1. Output 2nd, line 4

awk ' {print $ "\ T" $4} ' student.txt Name    Markfurong    fengj    -cang    

2. Output Df-h 1th, 3 lines

DF awk ' {print "\ t" $ $} ' Filesystem    Used/dev/mapper/vg_myfuture-lv_root    18G    13Gtmpfs    228K/dev/sda1    29M/ Dev/sr0    4. 4G

And cut doesn't make it.

[Email protected] ~]#DF-H |Cut-F1,3Filesystem Size used Avail use%mounted on/dev/mapper/vg_myfuture-lv_root 18G3.7G 13G at% /tmpfs 491M 228K 491M1%/dev/SHM/DEV/SDA1 477M 29M 424M7% /Boot/dev/sr04.4G4.4G0  -%/media/centos_6.6_final

3. Get the usage of/DEV/SDA1:

DF grep " /dev/sda1 " awk ' {print $} ' Cut " % " 1 7

4.BEGIN relationship expression, you can continue an action only if the relationship expression is satisfied first.

awk ' Begin{print "This is a test"}{print "\ T" $4} ' Student.txt This is a testname    Markfurong    fengj    -cang    

The 5.END will match after all the inputs have been processed.

awk ' End{print "This is a test"}{print "\ T" $4} ' student.txt Name    Markfurong    fengj    cang     Test

6. Extract the user name and ID

cat /etc/passwdgrepawk'begin{fs= ': "}{print" \ T "$"  Root    0Zabbix    Hadoop    501 user1     502

7. Extract the names of people with a score greater than 70

Cat grep awk ' $4>=70 {print $} ' Furongcang

8.awk by default with a space delimiter, use the '-f ' flag in awk to specify your delimiter

[Email protected] ~]#  echo'onemississippi,two mississippi,three mississippi,four Mississippi'awk'{print $4}' four Mississippi 

9. As long as the last field. The $NF variable built into awk represents the number of fields so that you can use it to grab the last element:

Echo ' One, three four ' awk ' {print $NF} '

The second-lowest field:

Cat awk ' {print $ (NF-1)} ' genderfff

Intermediate fields:

Cat awk ' {print $ ((NF/2) +1)} ' genderfff

Cross-line status of 10.awk

Echo ' One 1\ntwo 2 ' awk ' {sum+=$2} END {print sum} ' 3

awk Command Learning