Commands using head (314)

  • Get the user with the top number of logins

    Get an approximation of who the workstation is assigned to. You can wrap it in su - "$()" if you want to log into a shell as that user. Show Sample Output


    0
    last | grep -i console | grep -iv 'root' | cut -f 1 -d ' ' | sort | uniq -c | sort -nr | awk '{print $2}' | head -1
    phyxia · 2015-07-20 18:07:40 10
  • Generate a random string (for password, hash or whatever)

    Useful when you need to generate password or random hash string. If you need longer string adjust parameter for "head -c 20" Show Sample Output


    0
    dd if=/dev/urandom bs=1k count=1 2>/dev/null|LC_CTYPE=C tr -dc 'abcdefghijklmnopqrstuvwxyz0123456789!@#%^&*(-_=+)'|head -c 20
    nitrogear · 2015-07-25 21:24:28 9
  • ps to show child thread PIDs


    0
    ls -1 /proc/$(ps ax | grep <Process Name> | head -n 1 | awk '{print $1;}')/task | tail -n +2
    happymarmoset · 2015-10-06 07:44:48 10
  • Shows which commands you use the most.


    0
    cut -f1 -d" " ~/.bash_history | sort | uniq -c | sort -nr | head -n 30
    kenorb · 2015-10-09 16:11:37 10
  • Extract the URL of the first mp3 out of a podcast xml feed and add it it to current mpd playlist

    Quick way to get the URL of the most recent audio file out of a podcast xml feed without any fancy xml parsing tools. Just curl, grep and head


    0
    mpc add `curl -s http://link.to/podcast/feed.xml | grep -o 'https*://[^"]*mp3' | head -1`
    tbon3r · 2015-10-11 09:17:35 9
  • yet another random password generator.

    this one includes special characters. note some some chars may be disallowed on windows systems. *nix will allow pretty much any character in a password except a carriage return. you do not want non printing characters in your password, so this is limited to the printable chars displayed on a keyboard , less space and return. edited to fix minor typo Show Sample Output


    0
    tr -dc '[:print:]' < /dev/urandom | fold -w10 |head -n1 |sed 's/ //g'
    wr250 · 2016-01-09 13:43:16 12
  • Returns the N most recently modified files from anywhere 'below' (and including) the current working directory, in order, with details.

    Returns a list, with attributes (think `ls -l`), in reverse chronological order. N is a single numeric parameter. Robust against unfriendly filenames and directory structures. Show Sample Output


    0
    nmf() { find . -type f -printf '%T@ ' -print0 -printf '\n' | sort -rn | head -"$1" | cut -f2- -d" " | tr -d "\0" | tr "\n" "\0" | xargs -0 ls -Ulh; }
    incidentnormal · 2016-03-04 14:53:14 12
  • Display the top ten running processes - sorted by memory usage

    Display the top processes sorted by memory usage. This is mostly useful because it's easy to remember and can give me a quick 'top' view of a group of servers when used over pssh. (Though I'd recommend |head -10 to minimize the output). Show Sample Output


    0
    top -b -o +%MEM |head -17
    dak1n1 · 2016-03-16 22:14:34 12
  • Convert json files to tsv text blob

    Grabs the first JSON file in the directory, reads its keys, prints TSV, then prints all the json files' values as TSV. Nested objects appear as json. Unhappy times if your json has literal tabs in it. Show Sample Output


    0
    jq -r 'keys | join("\t")' $(ls -f *.json | head -1) && jq -Sr 'to_entries | [ .[] | .value | tostring ] | join("\t")' *.json
    drjeats · 2016-04-08 23:30:30 12
  • List latest 5 modified files recursively

    This command will find any named file types in / between two dates then will list all the metadata of those files in long format and human readable form. Adding a 't' flag to the ls command sorts the files by modified time. After all that the head -5 lists the first 5 which can be changed.


    0
    ls -laht `find / -name "*.*" -type f -newermt "2016-04-05" ! -newermt "2016-04-10"`|head -5
    ubercoo · 2016-04-19 14:26:23 10
  • Finding commands to create alias for

    by determining most popular use in history using percentage . Show Sample Output


    0
    history | awk '{CMD[$2]++;count++;}END { for (a in CMD)print CMD[a] " " CMD[a]/count*100 "% " a;}' | grep -v "./" | column -c3 -s " " -t | sort -nr | nl | head -n10
    turrtle13 · 2016-04-24 17:21:35 9
  • Password server

    This server can be access by a browser or other remote terminal with ncat. I have to use de test && break to allow ctrl-c to close. Show Sample Output


    0
    while [ 1 ]; do cat /dev/urandom | tr -dc ' -~' | head -c 10 | ncat -l 8080 &> /dev/null; test $? -gt 128 && break; done
    xxjcaxx · 2016-05-04 14:36:47 10
  • sorta apache logs by ip frequency


    0
    cat access.log | awk '{print $1}' | sort -n | uniq -c | sort -nr | head -20
    prees · 2016-05-05 20:52:03 13
  • This command watches the top 10 processes currently taking up the most memory with thread & other info, incase you don't want to use the TOP or HTOP command.

    This is a alternate command I like to use instead of TOP or HTOP to see what are the processes which are taking up the most memory on a system. It shows the username, process ID, CPU usage, Memory usage, thread ID, Number of threads associated with parent process, Resident Set Size, Virtual Memory Size, start time of the process, and command arguments. Then it's sorted by memory and showing the top 10 with head. This of course can be changed to suit you needs. I have a small system which is why Firefox is taking so much resources. Show Sample Output


    0
    watch -n .8 'ps -eaLo uname,pid,pcpu,pmem,lwp,nlwp,rss,vsz,start_time,args --sort -pmem| head -10'
    ubercoo · 2016-05-11 01:05:53 11
  • Find top 10 largest files in /var directory (including subdirectories)


    0
    find /var -type f -exec du -h {} \; | sort -rh | head -10
    jiananmail · 2016-05-31 00:21:32 10
  • who is the console user?

    Finds the login id of the user that owns the console. I use it to reset my touchpad after resume from suspend in /etc/pm/sleep.d/s99local


    0
    who | grep :0 | head -1 | cut -d " " -f 1
    mikef5410 · 2016-06-22 17:33:38 12
  • Find 20 most frequently-used shell commands from (bash history)


    0
    tr "\|\;" "\n" < ~/.bash_history | sed -e "s/^ //g" | cut -d " " -f 1 | sort | uniq -c | sort -rn | head -20
    turrtle13 · 2016-07-01 19:27:12 10
  • Display the top ten running processes sorted by the memory usage:


    0
    ps aux | awk '{if ($5 != 0 ) print $2,$5,$6,$11}' | sort -k2rn | head -10 | column -t
    turrtle13 · 2016-07-01 19:40:56 12
  • sort of automaticly install gems that are depend

    When bundle install sucks ...This runs isuckat_ruby.rb and when stderror matches find gem ' it will gem install what ever is missing ... Show Sample Output


    0
    gem install `ruby ./isuckat_ruby.rb 2>&1 | sed -e 's/.*find gem .//g' -e 's/ .*//g' | head -n 1`
    operat0r · 2016-08-03 19:41:27 13
  • Last shutdown date and time of a system


    0
    last -x | grep shutdown | head -1
    creepyjones · 2016-08-10 21:51:48 12
  • simulate Simultaneous connections with curl

    to simulating connections Simultaneous to specific server adress to test penetrations Show Sample Output


    0
    for i in {0..60}; do (curl -Is http://46.101.214.181:10101 | head -n1 &) 2>/dev/null; sleep 1; done;
    aysadk · 2017-01-15 14:32:02 16
  • stress test curl 60 connection simulate


    0
    for i in {0..60}; do (curl -Is http://<domain/ip> | head -n1 &) 2>/dev/null; sleep 1; done;
    aysadk · 2017-01-24 02:47:13 13
  • Find the top most 5 duplicate files in a folder

    To allow recursivity : find -type f -exec md5sum '{}' ';' | sort | uniq -c -w 33 | sort -gr | head -n 5 | cut -c1-7,41- Display only filenames : find -maxdepth 1 -type f -exec md5sum '{}' ';' | sort | uniq -c -w 33 | sort -gr | head -n 5 | cut -c43- Show Sample Output


    0
    find -maxdepth 1 -type f -exec md5sum '{}' ';' | sort | uniq -c -w 33 | sort -gr | head -n 5 | cut -c1-7,41-
    MaDCOw · 2017-02-09 11:36:31 18
  • Print nicely in columns a chunk of text that is separated by tab


    0
    head filename.txt | column -t -s $'\t'
    NLKNguyen · 2017-02-10 23:26:10 20
  • Execute the last line of output from the previous command

    alex@alex-box:~$ sl The program 'sl' is currently not installed. You can install it by typing: sudo apt-get install sl alex@alex-box:~$ dolast Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: sl 0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.


    0
    alias dolast='$( $(history 2| head -n 1| sed "s/.* //") 2>&1 | tail -n 1)'
    aheinous · 2017-02-25 01:26:49 19
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Copy a directory recursively without data/files

Display kernel profile of currently executing functions in Solaris.
Lockstat will sample the kernel 977 times per second, and print out the functions that it sees executing on the CPU during the sample. The -s 10 switch tells lockstsat to not only print that function, but also show the call stack (up to 10 deep).

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

print/scan lines starting at record ###
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.

Debug SSH at the Maximum Verbosity Level
When debugging an ssh connection either to optimize your settings ie compression, ciphers, or more commonly for debugging an issue connecting, this alias comes in real handy as it's not easy to remember the '-o LogLevel=DEBUG3' argument, which adds a boost of debugging info not available with -vvv alone. Especially useful are the FD info, and the setup negotiation to create a cleaner, faster connection.

Restrict the bandwidth for the SCP command
the command is obvious, I know, but maybe not everyone knows that using the parameter "-l" you can limit the use of bandwidth command scp. In this example fetch all files from the directory zutaniddu and I copy them locally using only 10 Kbs

Convert files from DOS line endings to UNIX line endings
This method will also convert mac line endings.

Check if *hardware* is 32bit or 64bit
This command tell you if your hardware is 32 or 64 bits even if you install a 32bits OS on a 64 bits hardware. If your distro don't support the -q switch, try doing : $ grep &>/dev/null '\' /proc/cpuinfo && echo 64 bits || echo 32 bits

Reinstall Grub

recursive base64 encoding -- Cipher for the Poor ?
Just for fun, I searched a simple way to encrypt some text. Simple base64 encoding seemed a good start so I decided to "amplify" encoding using repeted base64 encoding. Of course, this is not really secure but can be useful to hide datas to most part of humans ;). Do not hesitate to provide better solutions or else.

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