Awk snippets

Cool snippets i’ve found online. Most of which i’ve gathered from ChatGPT

• Format drive info

lsblk |awk 'NR==1{print $0" DEVICE-ID(S)"}NR>1{dev=$1;printf $0" ";system("find /dev/disk/by-id -lname \"*"dev"\" -printf \" %p\"");print "";}'|grep -v -E 'part|lvm'

• Find pattern in file

awk '/pattern/ { count++ } END { print count }' file.txt

• Sum all values of a column

awk '{ sum += $2 } END { print sum }' file.txt

• Print a specific column

awk '{ print $3 }' file.txt

• Filter and print specific fields

awk '$1 ~ /ERROR/ { print $1, $2, $5 }' log.txt

• Field Delimiters for CSV

awk -F, '{ print $1, $3 }' data.csv

• Print Non-Matching lines

awk '!/pattern/' file.txt 

• Remove duplicate lines

awk '!seen[$0]++' file.txt 

• Print lines with Line number and Field Count

awk '{ print NR ": (" NF " fields) -> " $0}' file.txt 

• Convert Lines into a Single Comma-Separated Line

awk '{ 
  if (NR == 1) {
    # For the first line, just print
    printf "%s", $0
  } else {
    # For subsequent lines, prepend a comma
    printf ",%s", $0
  }
} END { printf "\n" }' file.txt

Note : You’d be better off using a short sed snippet like this instead paste -sd ',' file.txt

• Print a range of lines between two patterns

awk '/BEGIN_PATTERN/,/END_PATTERN/' file.txt 

• Group and list files by extension

    ls -1 | awk -F. '/\./ {ext[$NF]++} END {for (e in ext) print e}' | sort