Longest line in a file

Question

I\'m looking for a simple way to find the length of the longest line in a file. Ideally, it would be a simple bash shell command instead of a script.

Answer 1

I'm in a Unix environment, and work with gzipped files that are a few GBs in size. I tested the following commands using a 2 GB gzipped file with record length of 2052.

1. zcat <gzipped file> | wc -L

and

2. zcat <gzipped file> | awk '{print length}' | sort -u

The times were on avarage

1. 117 seconds

2. 109 seconds

Here is my script after about 10 runs.

START=$(date +%s) ## time of start

zcat $1 |  wc -L

END=$(date +%s) ## time of end
DIFF=$(( $END - $START ))
echo "It took $DIFF seconds"

START=$(date +%s) ## time of start

zcat $1 |  awk '{print length}' | sort -u

END=$(date +%s) ## time of end
DIFF=$(( $END - $START ))
echo "It took $DIFF seconds"

Answer 2

Just for fun, here's the Powershell version:

cat filename.txt | sort length | select -last 1

And to just get the length:

(cat filename.txt | sort length | select -last 1).Length

Answer 3

wc -L < filename

gives

101

Answer 4

perl -ne 'print length()."  line $.  $_"' myfile | sort -nr | head -n 1

Prints the length, line number, and contents of the longest line

perl -ne 'print length()."  line $.  $_"' myfile | sort -n

Prints a sorted list of all lines, with line numbers and lengths

. is the concatenation operator - it is used here after length()
$. is the current line number
$_ is the current line

Answer 5

Looks all the answer do not give the line number of the longest line. Following command can give the line number and roughly length:

$ cat -n test.txt | awk '{print "longest_line_number: " $1 " length_with_line_number: " length}' | sort -k4 -nr | head -3
longest_line_number: 3 length_with_line_number: 13
longest_line_number: 4 length_with_line_number: 12
longest_line_number: 2 length_with_line_number: 11

Answer 6

Here are references of the anwser

cat filename | awk '{print length, $0}'|sort -nr|head -1

http://wtanaka.com/node/7719