awk

awk "BEGIN {FS='o'} {print $1,$3} END{print 'Total Rows=',NR}"

# Print every line in a file:	
awk '{print}' test.txt

# Print the lines which contains the given pattern:
awk '/test/ {print}' test.txt
awk '/test/' test.txt

# Print the fields 1 and 4 with delimeter whitespace:
awk '{print $1, $4}' test.txt
awk '{print $1 $4}' test.txt

# Display a block of test starts with the word start and ends with the word end:
awk '/start/,/stop/' test.txt

-f flag will execute specifying the name of the script file:
awk -f script.awk test.txt

Number the lines:
awk '{print NR, $0}' test.txt

# Use of NR built-in variables (Display Line Number):
awk '{print NR,$0}' test.txt

# Another use of NR built-in variables (Display Line From 3 to 6):
awk 'NR==3, NR==6 {print NR,$0}' test.txt

# Print the first item with its row number (NR), separated by "– " from each line:
awk '{print NR "- " $1 }' test.txt

# Use of NF built-in variables (Display Last Field):
awk '{print $1,$NF}' test.txt 

# Print any non empty line if present:
awk 'NF < 0' test.txt
awk 'NF == 0 {print NR}' test.txt
awk 'NF <= 0 {print NR}' test.txt

awk 'BEGIN {print "FS = " FS}' | cat -vte

awk 'BEGIN {print "RS = " RS}' | cat -vte

awk 'BEGIN {print "OFS = " OFS}' | cat -vte

awk 'BEGIN {print "ORS = " ORS}' | cat -vte

# To find the length of the longest line present in the file:  
awk '{ if (length($0) > max) max = length($0) } END { print max }' test.txt

# To count the lines in a file:  
awk 'END { print NR }' test.txt 

# Printing lines with more than 10 characters:  
awk 'length($0) > 10' test.txt 

# To find/check for any string in any specific column:  
awk '{ if($3 == "B6") print $0;}' test.txt

# Print the squares of first numbers from 1 to n say 6:  
awk 'BEGIN { for(i=1;i<=6;i++) print "square of", i, "is",i*i; }'