Useful Linux commands to quickly analyze a log

 1)   Limit the output to 'n' characters per line in a search .

In the above example, it is limited to 400 bytes.

cat sample_file.log | cut -b 1-400 | less

2) In a large file, count the total lines starting with ^1 in the first column

 sed '1 d' FILE.csv | cut -d',' -f1 | sort | grep '^1*' | wc -l

sed '1 d' - delete the first line i.e. the header generally in a CSV

FILE.csv - File in question to analyze

cut -d',' -f1 -  Split the file using the ',' as a separator ('d','), and then retain the first column (f1)

sort - order the output in ascending manner

wc -l - total number of lines in the file