linux截取日志某一列

awk '{print $n}' filename

2023-04-01 12:34:56 INFO User logged in
2023-04-01 12:35:01 ERROR Failed to connect to database
2023-04-01 12:35:10 INFO User logged out

awk '{print $1}' example.log

2023-04-01
2023-04-01
2023-04-01

awk '{print $3}' example.log

INFO
ERROR
INFO

awk '{for(i=4;i<=NF;i++) printf "%s ", $i; print ""}' example.log

User logged in 
Failed to connect to database 
User logged out 

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

awk '{print $0}' example.log | while read -r line; do
    echo "$line" | awk '{print $4}'
done

awk '$3 == "ERROR" {print $0}' example.log