gawk - used for pattern scanning and processing language
$ cat staff.txt
arun 0001
babu 0002
chandru 0003
dhana 0004
kiran 0005
raj 0006
sunil 0007
teja 0008
To print current count of the number of input line
$ gawk '{print NR "-" $1 }' staff.txt
gawk prints every line of data from the input line
$ gawk '{print}' staff.txt
To print the lines matching with the given pattern
$ gawk '/babu/ {print}' staff.txt
To print the second column records of the input file
$ gawk '{print $2}' staff.txt
To display count of lines
$ gawk '{print NR, $0}' staff.txt
To find the length of the longest line present in the file
gawk '{ if (length($0) > max) max = length($0) } END { print max }'
staff.txt
To count the lines in a file
$ gawk 'END { print NR }' staff.txt
To print lines with more than 11 characters
$ gawk 'length($0) > 11' staff.txt
regards,
T.Dhanasekar