Tail a log file with long lines truncated

tail -f logfile.log | cut -b 1-80
This truncates any lines longer than 80 characters. Also useful for looking at different parts of the line, e.g. cut -b 50-100 shows columns 50 through 100.

3
2009-03-26 18:41:57

These Might Interest You

  • tells you the number of lines in said file, and then tail the last 100 lines ( or how many are messed up) then u take the total amount of lines and then subract the 100 or so lines u DONT WANT, then do a head -n $new_number and then redirect it to new file.db


    -1
    cat -n $file | tail -n 100 && head -n number-of-lines-you-want-to-keep > newfile
    bbelt16ag · 2009-02-15 01:02:10 0
  • You can actually do the same thing with a combination of head and tail. For example, in a file of four lines, if you just want the middle two lines: head -n3 sample.txt | tail -n2 Line 1 --\ Line 2 } These three lines are selected by head -n3, Line 3 --/ this feeds the following filtered list to tail: Line 4 Line 1 Line 2 \___ These two lines are filtered by tail -n2, Line 3 / This results in: Line 2 Line 3 being printed to screen (or wherever you redirect it).


    0
    head -n1 sample.txt | tail -n1
    gtcom · 2011-06-14 17:45:04 0
  • tail() { thbin="/usr/bin/tail"; if [ "${1:0:1}" != "-" ]; then fc=$(($#==0?1:$#)); lpf="$((($LINES - 3 - 2 * $fc) / $fc))"; lpf="$(($lpf<1?2:$lpf))"; [ $fc -eq 1 ] && $thbin -n $lpf "$@" | /usr/bin/fold -w $COLUMNS | $thbin -n $lpf || $thbin -n $lpf "$@"; else $thbin "$@"; fi; unset lpf fc thbin; } This is a function that implements an improved version of tail. It tries to limit the number of lines so that the screen is filled completely. It works with pipes, single and multiple files. If you add different options to tail, they will overwrite the settings from the function. It doesn't work very well when too many files (with wrapped lines) are specified. Its optimised for my three-line prompt. It also works for head. Just s/tail/head/g Don't set 'thbin="tail"', this might lead to a forkbomb.


    -1
    tail() { thbin="/usr/bin/tail"; if [ "${1:0:1}" != "-" ]; then fc=$(($#==0?1:$#)); lpf="$((($LINES - 3 - 2 * $fc) / $fc))"; lpf="$(($lpf<1?2:$lpf))"; [ $fc -eq 1 ] && $thbin -n $lpf "$@" | /usr/bin/fold -w $COLUMNS | $thbin -n $lpf || $thbin -n $lpf...
    fpunktk · 2012-03-23 19:00:30 0
  • Useful for finding newly added lines to a file, tail + can be used to show only the lines starting at some offset. A syslog scanner would look at the file for the first time, then record the end_of_file record number using wc -l. Later (hours, days), scan only at the lines that were added since the last scan. Show Sample Output


    1
    tail +### MYFILE
    pooderbill · 2015-04-23 11:49:15 0

What Others Think

Or even smarter, use "tput cols" to tell you the width of the terminal: tail -f logfile.log | cut -b -$(tput cols)
flatcap · 481 weeks and 4 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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