Commands using tail (292)

  • find the longest command in your history


    3
    history | perl -lane '$lsize{$_} = scalar(@F); if($longest<$lsize{$_}) { $longest = $lsize{$_}; print "$_"; };' | tail -n1
    salparadise · 2009-03-19 02:52:30 6
  • Tail a log file with long lines truncated

    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
    tail -f logfile.log | cut -b 1-80
    plasticboy · 2009-03-26 18:41:57 11
  • Output system statistics every 5 seconds with timestamp

    See man vmstat for information about the statistics. This does the same thing without the timestamp: vmstat 5 Show Sample Output


    3
    while [ 1 ]; do echo -n "`date +%F_%T`" ; vmstat 1 2 | tail -1 ; sleep 4; done
    plasticboy · 2009-03-26 19:16:55 14
  • Show the 20 most CPU/Memory hungry processes

    This command will show the 20 processes using the most CPU time (hungriest at the bottom). You can see the 20 most memory intensive processes (hungriest at the bottom) by running: ps aux | sort +3n | tail -20 Or, run both: echo "CPU:" && ps aux | sort +2n | tail -20 && echo "Memory:" && ps aux | sort +3n | tail -20


    3
    ps aux | sort +2n | tail -20
    dopeman · 2009-03-31 12:03:34 10
  • Delete all but the latest 5 files

    yes 6 (tail from 6th line)


    3
    ls -t | tail +6 | xargs rm
    negyvenot · 2009-09-16 06:33:07 3
  • Figure out your work output for the day

    Figures out what has changed in the last 12 hours. Change the author to yourself, change the time since to whatever you want. Show Sample Output


    3
    git diff --stat `git log --author="XXXXX" --since="12 hours ago" --pretty=oneline | tail -n1 | cut -c1-40` HEAD
    askedrelic · 2009-11-04 01:41:33 3
  • Updated top ten memory utilizing processes (child/instance aggregation) now with percentages of total RAM

    Prints the top 10 memory consuming processes (with children and instances aggregated) sorted by total RSS and calculates the percentage of total RAM each uses. Please note that since RSS can include shared libraries it is possible for the percentages to add up to more that the total amount of RAM, but this still gives you a pretty good idea. Also note that this does not work with the mawk version of awk, but it works fine with GNU Awk which is on most Linux systems. It also does not work on OS X. Show Sample Output


    3
    TR=`free|grep Mem:|awk '{print $2}'`;ps axo rss,comm,pid|awk -v tr=$TR '{proc_list[$2]+=$1;} END {for (proc in proc_list) {proc_pct=(proc_list[proc]/tr)*100; printf("%d\t%-16s\t%0.2f%\n",proc_list[proc],proc,proc_pct);}}'|sort -n |tail -n 10
    d34dh0r53 · 2010-03-27 01:34:50 7
  • Find out what the day ends in

    Several people have submitted commands to do this, but I think this is the simplest solution. It also happens to be the most portable one: It should work with any sh or csh derived shell under any UNIX-like OS. Oh by the way, with my German locale ($LC_TIME set appropriately) it prints "g" most of the time, and sometimes (on Wednesdays) it prints "h". It never prints "y". Show Sample Output


    3
    date +%A | tail -2c
    inof · 2010-04-08 15:14:06 6
  • Monitor a file with tail with timestamps added


    3
    tail -f file |xargs -IX printf "$(date -u)\t%s\n" X
    unefunge · 2010-11-25 11:23:13 5
  • Display top Keywords from history


    3
    history | awk '{print $2}' | awk 'BEGIN {FS="|"}{print $1}' | sort | uniq -c | sort -n | tail | sort -nr
    secretgspot · 2011-03-12 05:58:21 3
  • View all new log messages in real time with color


    3
    find /var/log -iregex '.*[^\.][^0-9]+$' -not -iregex '.*gz$' 2> /dev/null | xargs tail -n0 -f | ccze -A
    brejktru · 2011-04-17 18:09:25 3
  • read squid logs with human-readable timestamp

    Show Sample Output


    3
    tail -f /var/log/squid/access.log | perl -p -e 's/^([0-9]*)/"[".localtime($1)."]"/e'
    godzillante · 2011-07-06 08:55:27 7
  • Script Terminal Session

    script -f /tmp/foo will place all output of the terminal, including carriage returns, to a file. This file can be tail dash-eff'ed by one or more other terminals to display the information of the main terminal. Good way to share one's screen on short notice. Note: This produces a very accurate output, but that includes depending on the size of your terminal to be the same. You can clear screens or even resize the terminal for others using this function; I use it in conjunction with the "mid" command in my list. Show Sample Output


    3
    script -f /tmp/foo; tail -f /tmp/foo
    robinsonaarond · 2011-11-22 15:16:08 23
  • Deleting / Ignoring lines from the top of a file

    Output lines starting at line 2.


    3
    tail -n +2 foo.txt
    kaushalmehra · 2012-09-13 20:54:36 4
  • Recover username and password for Technicolor TC7200 admin page (vulnerability)

    The router Technicolor TC7200 has an exploit where the file http://192.168.0.1/goform/system/GatewaySettings.bin is open for unauthenticated access. Even though it is binary, the 2 last strings are the username and password for the pages for router management. It can be read using the 'strings' command, 'hexdump -C' or a hexadecimal editor. (default user/password = admin/admin) Reveals more configuration, including SSID name and Key for the wifi network: wget -q -O - http://192.168.0.1/goform/system/GatewaySettings.bin Hexadecimal dump of the file: wget -q -O - http://192.168.0.1/goform/system/GatewaySettings.bin | hexdump -C Show Sample Output


    3
    wget -q -O - http://192.168.0.1/goform/system/GatewaySettings.bin | strings | tail -n 2
    paulera · 2016-05-03 23:03:55 13
  • Quickly add a new user to all groups the default user is in

    This is a standard procedure for me, whenever I set up a new Raspberry Pi system. Because the default user is "pi", I quickly replace it with my own (e.g. "kostis"), but I have to substitute that user to all of pi's groups first, before deleting the default account. xargs helps a lot with that in a single line, while avoiding boring "for" loops. For everything trickier, there's always "parallel" :)


    3
    groups pi | xargs -n 1 | tail -n +4 | xargs -n 1 sudo adduser kostis
    kostis · 2022-01-25 07:20:09 449
  • List last opened tabs in firefox browser

    Tuned for short command line - you can set the path to sessionstore.js more reliable instead of use asterixes etc. Usable when you are not at home and really need to get your actual opened tabs on your home computer (via SSH). I am using it from my work if I forgot to bookmark some new interesting webpage, which I have visited at home. Also other way to list tabs when your firefox has crashed (restoring of tabs doesn't work always). This script includes also tabs which has been closed short time before.


    2
    F="$HOME/.moz*/fire*/*/session*.js" ; grep -Go 'entries:\[[^]]*' $F | cut -d[ -f2 | while read A ; do echo $A | sed s/url:/\n/g | tail -1 | cut -d\" -f2; done
    b2e · 2009-05-21 21:58:42 4
  • Get table column names from an MySQL-database in comma-seperated form


    2
    mysql -u<user> -p<password> -s -e 'DESCRIBE <table>' <database> | tail -n +1 | awk '{ printf($1",")}' | head -c -1
    Cowboy · 2009-08-17 12:54:44 3
  • get diskusage of files modified during the last n days

    get diskusage of files (in this case logfiles in /var/log) modified during the last n days: sudo find /var/log/ -mtime -n -type f | xargs du -ch n -> last modified n*24 hours ago Numeric arguments can be specified as +n for greater than n, -n for less than n, n for exactly n. => so 7*24 hours (about 7 days) is -7 sudo find /var/log/ -mtime -7 -type f | xargs du -ch | tail -n1 Show Sample Output


    2
    sudo find /var/log/ -mtime -7 -type f | xargs du -ch | tail -n1
    alvinx · 2009-08-27 14:18:47 5
  • A function to find the newest file in a directory


    2
    find /path/to/dir -type f -printf "%T@|%p\n" 2>/dev/null | sort -n | tail -n 1| awk -F\| '{print $2}'
    glennie · 2010-02-04 15:13:27 4
  • Find how much of your life you've wasted coding in the current directory

    Finds all C++, Python, SWIG files in your present directory (uses "*" rather than "." to exclude invisibles) and counts how many lines are in them. Returns only the last line (the total). Show Sample Output


    2
    find * \( -name "*.[hc]pp" -or -name "*.py" -or -name "*.i" \) -print0 | xargs -0 wc -l | tail -n 1
    neologism · 2010-03-25 18:58:29 4
  • Give {Open,True}Type files reasonable names

    Just a quick hack to give reasonable filenames to TrueType and OpenType fonts. I'd accumulated a big bunch of bizarrely and inconsistently named font files in my ~/.fonts directory. I wanted to copy some, but not all, of them over to my new machine, but I had no idea what many of them were. This script renames .ttf files based on the name embedded inside the font. It will also work for .otf files, but make sure you change the mv part so it gives them the proper extension. REQUIREMENTS: Bash (for extended pattern globbing), showttf (Debian has it in the fontforge-extras package), GNU grep (for context), and rev (because it's hilarious). BUGS: Well, like I said, this is a quick hack. It grew piece by piece on the command line. I only needed to do this once and spent hardly any time on it, so it's a bit goofy. For example, I find 'rev | cut -f1 | rev' pleasantly amusing --- it seems so clearly wrong, and yet it works to print the last argument. I think flexibility in expressiveness like this is part of the beauty of Unix shell scripting. One-off tasks can be be written quickly, built-up as a person is "thinking aloud" at the command line. That's why Unix is such a huge boost to productivity: it allows each person to think their own way instead of enforcing some "right way". On a tangent: One of the things I wish commandlinefu would show is the command line HISTORY of the person as they developed the script. I think it's that conversation between programmer and computer, as the pipeline is built piece-by-piece, that is the more valuable lesson than any canned script. Show Sample Output


    2
    shopt -s extglob; for f in *.ttf *.TTF; do g=$(showttf "$f" 2>/dev/null | grep -A1 "language=0.*FullName" | tail -1 | rev | cut -f1 | rev); g=${g##+( )}; mv -i "$f" "$g".ttf; done
    hackerb9 · 2010-04-30 09:46:45 6
  • How to backup hard disk timely?

    'data' is the directory to backup, 'backup' is directory to store snapshots. Backup files on a regular basis using hard links. Very efficient, quick. Backup data is directly available. Same as explained here : http://blog.interlinked.org/tutorials/rsync_time_machine.html in one line. Using du to check the size of your backups, the first backup counts for all the space, and other backups only files that have changed. Show Sample Output


    2
    rsync -av --link-dest=$(ls -1d /backup/*/ | tail -1) /data/ /backup/$(date +%Y%m%d%H%M)/
    dooblem · 2010-08-05 19:36:24 6
  • Continually monitor things

    You can use this one-liner for a quick and dirty (more customizable) alternative to the watch command. The keys to making this work: everything exists in an infinite loop; the loop starts with a clear; the loop ends with a sleep. Enter whatever you'd like to keep an eye on in the middle. Show Sample Output


    2
    while (true); do clear; uname -n; echo ""; df -h /; echo ""; tail -5 /var/log/auth.log; echo ""; vmstat 1 5; sleep 15; done
    roknir · 2010-08-23 04:37:58 7
  • Find directory depth

    Returns a the directory depth.


    2
    find . -printf '%d\n' | sort -n | tail -1
    dustindorroh · 2011-04-25 18:38:12 7
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Find and display most recent files using find and perl
This pipeline will find, sort and display all files based on mtime. This could be done with find | xargs, but the find | xargs pipeline will not produce correct results if the results of find are greater than xargs command line buffer. If the xargs buffer fills, xargs processes the find results in more than one batch which is not compatible with sorting. Note the "-print0" on find and "-0" switch for perl. This is the equivalent of using xargs. Don't you love perl? Note that this pipeline can be easily modified to any data produced by perl's stat operator. eg, you could sort on size, hard links, creation time, etc. Look at stat and just change the '9' to what you want. Changing the '9' to a '7' for example will sort by file size. A '3' sorts by number of links.... Use head and tail at the end of the pipeline to get oldest files or most recent. Use awk or perl -wnla for further processing. Since there is a tab between the two fields, it is very easy to process.

Put public IP address in a variable

list files recursively by size

Scans for open ports using telnet

Efficient count files in directory (no recursion)
$ time perl -e 'if(opendir D,"."){@a=readdir D;print $#a - 1,"\n"}' 205413 real 0m0.497s user 0m0.220s sys 0m0.268s $ time { ls |wc -l; } 205413 real 0m3.776s user 0m3.340s sys 0m0.424s ********* ** EDIT: turns out this perl liner is mostly masturbation. this is slightly faster: $ find . -maxdepth 1 | wc -l sh-3.2$ time { find . -maxdepth 1|wc -l; } 205414 real 0m0.456s user 0m0.116s sys 0m0.328s ** EDIT: now a slightly faster perl version $ perl -e 'if(opendir D,"."){++$c foreach readdir D}print $c-1,"\n"' sh-3.2$ time perl -e 'if(opendir D,"."){++$c foreach readdir D}print $c-1,"\n"' 205414 real 0m0.415s user 0m0.176s sys 0m0.232s

Create a thumbnail from a video file

Monitor memory fine-grained usage (e.g. firefox)
Sometimes top/htop don't give the fine-grained detail on memory usage you might need. Sum up the exact memory types you want

Clear terminal Screen

user 'tr' to convert mixed case in a file to lower case
convert mixed case in a file to lower case

drop first column of output by piping to this

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