The awk is a utility developed by Aho, Weinberger and Kerninghan (AWK). It is a pattern scanning and processing language.By default it reads from standard input and writes to standard output.
The awk programs can be used in two ways.
a.Commandline
awk ‘pattern {print}’ input_files
awk ‘/regular expression/ {print}’ input_filesb.Program file
awk -f awk_script input_file
Let’s take below file for awk processing
File: myrecord
EMPID_001 SBAL C005 DEP_SALES
EMPID_002 GIRI C008 DEP_ENGG
EMPID_003 JAVV C001 DEP_HR
EMPID_004 SIKD C011 DEP_HR
EMPID_005 FARO C204 DEP_ENGG
EMPID_006 MABR C012 DEP_SALES
a. Simple awk command to print the file
awk ‘{print}’ myrecord
EMPID_001 SBAL C005 DEP_SALES
EMPID_002 GIRI C008 DEP_ENGG
EMPID_003 JAVV C001 DEP_HR
EMPID_004 SIKD C011 DEP_HR
EMPID_005 FARO C204 DEP_ENGG
EMPID_006 MABR C012 DEP_SALES
b. Print employees in SALES
awk ‘/DEP_SALES/ {print}’ myrecord
awk ‘/DEP_SALES/ {print}’ myrecord
EMPID_001 SBAL C005 DEP_SALES
EMPID_006 MABR C012 DEP_SALES
c. Print only empolyee names and their department (Splitting the fields)
awk ‘{print $2,$4}’ myrecord
awk ‘{print $2,$4}’ myrecord
SBAL DEP_SALES
GIRI DEP_ENGG
JAVV DEP_HR
SIKD DEP_HR
FARO DEP_ENGG
MABR DEP_SALES
d.Print the record with line numbers (NR: Print line numbers)
awk ‘{print NR,$0}’ myrecord
awk ‘{print NR,$0}’ myrecord
1 EMPID_001 SBAL C005 DEP_SALES
2 EMPID_002 GIRI C008 DEP_ENGG
3 EMPID_003 JAVV C001 DEP_HR
4 EMPID_004 SIKD C011 DEP_HR
5 EMPID_005 FARO C204 DEP_ENGG
6 EMPID_006 MABR C012 DEP_SALESawk ‘{print NR,$4}’ myrecord
1 DEP_SALES
2 DEP_ENGG
3 DEP_HR
4 DEP_HR
5 DEP_ENGG
6 DEP_SALES
e. Print the lines 4-6 from myrecord
awk ‘NR==4, NR==6 {print NR,$0}’ myrecord
awk ‘NR==4, NR==6 {print NR,$0}’ myrecord
4 EMPID_004 SIKD C011 DEP_HR
5 EMPID_005 FARO C204 DEP_ENGG
6 EMPID_006 MABR C012 DEP_SALES
f. Print first field with line numbers
awk ‘{print NR “- ” $1 }’ myrecord
1- EMPID_001
2- EMPID_002
3- EMPID_003
4- EMPID_004
5- EMPID_005
6- EMPID_006
g.Print only the last field (NF: Display Last Field)
awk ‘{print $NF}’ myrecord
DEP_SALES
DEP_ENGG
DEP_HR
DEP_HR
DEP_ENGG
DEP_SALES
clean explanation on this topic. thank you so much mamĀ