Commands using cat (514)

  • format txt as table

    Show Sample Output


    2
    cat /etc/passwd | column -nts:
    kev · 2011-08-31 02:08:20 6
  • Get a list of IP Addresses that have failed to login via SSH

    This command shows a sorted list of the IP addresses from which there have been authentication errors via SSH (possible script kiddies trying to gain access to your server), it eliminates duplicates so it's easier to read, but you can remove the "uniq" command at the end, or even do a "uniq -c" to have a count of how many times each IP address shows in the log (the path to the log may vary from system to system) Show Sample Output


    2
    cat /var/log/auth.log | grep -i "pam_unix(sshd:auth): authentication failure;" | cut -d' ' -f14,15 | cut -d= -f2 | sort | uniq
    JohnQUnknown · 2011-10-25 04:58:09 8
  • Apache CLF access log format to CSV converter

    - excel date compatible with a separate hour field - added a fixed 1 for easier request counter aggregation - split URL in directory, filename, fileext, query - used with tomcat valve with response bytes replaced by elapsed time Show Sample Output


    2
    #(see sample) $ cat x | perl -pe 'BEGIN{ print "TIME;...\n"; } s!(\S+) - (\S+) - \[(\d\d)/(\S\S\S)/(\S+):(\d\d):(\d\d:\d\d) \S+\] "(\S+) (.*/)(\S+)(?:\.([^?]*)(\?\S*)?) HTTP/\S+" (\d+) (\S+)!$3-$4-$5 $6:$7;$6;$2;$1;$8;$13;1;$14;$11;$10;$9;$12;!' > x.csv
    hute37 · 2012-02-10 16:58:50 3
  • The scene in the Shining (Stanley Kubrick)

    Let's take a rest. How about watch a horror? The Shining http://en.wikipedia.org/wiki/The_Shining_(film) Show Sample Output


    2
    yes "" | cat -n | awk '{print "S=`echo All work and no play makes Jack a dull boy. | cut -c",($1 - 1) % 43 + 1 "`;echo -n \"$S\";seq 500000 > /dev/null"}'| bash
    nati · 2012-04-08 07:53:43 26
  • merge pdf using bash brace exansion

    merge pdf from pg_0001.pdf until pg_0009.pdf into MyFile.pdf


    2
    pdftk pg_000{1..9}.pdf cat output MyFile.pdf
    eastwind · 2012-08-27 08:57:00 4
  • Copy ssh keys to user@host to enable password-less ssh logins.

    Alternative for machines without ssh-copy-id


    2
    cat ~/.ssh/id_rsa.pub | ssh user@host 'cat >> ~/.ssh/authorized_keys'
    eneko · 2012-12-08 17:00:47 15
  • Limit the transfer rate and size of data over a pipe

    This example will close the pipe after transferring 100MB at a speed of 3MB per second.


    2
    cat /dev/zero | pv -L 3m -Ss 100m > /dev/null
    bugmenot · 2012-12-15 10:17:52 5
  • chroot, bind mount without root privilege/setup

    PRoot is a user-space implementation of chroot, mount --bind, and binfmt_misc. This means that users don't need any privileges or setup to do things like using an arbitrary directory as the new root filesystem, making files accessible somewhere else in the filesystem hierarchy, or executing programs built for another CPU architecture transparently through QEMU user-mode. Also, developers can use PRoot as a generic Linux process instrumentation engine thanks to its extension mechanism, see CARE for an example. Technically PRoot relies on ptrace, an unprivileged system-call available in every Linux kernel. https://github.com/cedric-vincent/PRoot Show Sample Output


    2
    proot -r /media/user/ubuntu12.10/ cat /etc/motd
    totti · 2014-01-21 07:50:22 15
  • Generate random password on Mac OS X

    Feel free to put this in your ~/.profile: random(){ cat /dev/urandom | env LC_CTYPE=C tr -dc $1 | head -c $2; echo; } Then use it to generate passwords: random [:alnum:] 16 Or DNA sequences: random ACGT 256


    2
    cat /dev/urandom | env LC_CTYPE=C tr -dc a-zA-Z0-9 | head -c 16; echo
    yakovlev · 2014-02-05 15:04:07 6
  • Merge Multiple PDFs

    Merge Multiple PDFs In Alphabetical Order


    2
    pdftk *.pdf cat output merged.pdf
    o0110o · 2014-03-02 01:53:37 7
  • Convert epoch date to human readable date format in a log file.


    2
    cat /var/log/mosquitto/mosquitto.log | awk -F : '{"date -d @"$1 |& getline D; print D, $0}'
    ifebi · 2019-06-09 07:35:25 39
  • Convert tab separate file (TSV) to JSON with jq

    With this command you can convert a tab separate file (TSV) into a JSON file with jq. For example, this input.tsv i-0b9adca882e5e6326 172.16.0.188 i-088dd69e5c3624888 172.16.0.102 i-0e70eac180537d4aa 172.16.0.85 will produce the showed output. Show Sample Output


    2
    cat input.tsv | jq --raw-input --slurp 'split("\n") | map(split("\t")) | .[0:-1] | map( { "id": .[0], "ip": .[1] } )'
    nordri · 2019-10-01 10:52:35 229
  • Convert CSV to JSON with miller

    Using the csv tool `miller` you can transform a csv file into a json array of objects, where the properties are the values of the csv header line and the values are the values of the subsequent lines. Show Sample Output


    2
    mlr --c2j --jlistwrap cat file.csv
    pepa65 · 2019-12-06 07:16:58 106
  • parse and format IP:port currently in listen state without net tools

    Useful for containers and environments where you need to know if a port is currently in listen mode but you have not easy way or privileges to install net-tools like netstat or ss. "0A" is the code for listen state. The IP hex is reverse order and all in hex format. Show Sample Output


    2
    cat /proc/net/tcp | grep " 0A " | sed 's/^[^:]*: \(..\)\(..\)\(..\)\(..\):\(....\).*/echo $((0x\4)).$((0x\3)).$((0x\2)).$((0x\1)):$((0x\5))/g' | bash
    glaudiston · 2020-05-23 12:36:21 152
  • cpuinfo


    1
    cat /proc/cpuinfo
    kumara · 2009-02-05 12:46:50 38
  • Type strait into a file from the terminal.

    Takes input from the connected terminal and dumps it to the specified file. Stop writing and close file with control + D or the end of line character. Useful for copying+pasting large blobs of text over SSH to a new machine. Show Sample Output


    1
    cat /dev/tty > FILE
    Jo · 2009-02-25 01:43:47 11
  • find distro name / release version


    1
    $ cat /etc/*-release
    unixmonkey1855 · 2009-02-26 21:04:43 8
  • Display duplicated lines in a file

    Displays the duplicated lines in a file and their occuring frequency.


    1
    cat file.txt | sort | uniq -dc
    Vadi · 2009-03-21 18:15:14 7
  • remove comments from xml

    xml with verbose commenting can be difficult to read. remove comments from xml.


    1
    cat <filename> | perl -e '$/ = ""; $_ = <>; s/<!--.*?-->//gs; print;'
    unixx · 2009-04-15 20:29:11 37
  • Listen to a file

    replace "/usr/src/linux/kernel/signal.c" with any file you want and listen to its output ! :P you can also replace "cat" with "echo" or anything you can come up with have fun :-}


    1
    while true; do cat /usr/src/linux/kernel/signal.c > /dev/dsp; done
    JesusSuperstar · 2009-05-16 14:44:57 6
  • Check wireless link quality with dialog box

    The variable WIRELESSINTERFACE indicates your wireless interface


    1
    while [ i != 0 ]; do sleep 1 | dialog --clear --gauge "Quality: " 0 0 $(cat /proc/net/wireless | grep $WIRELESSINTERFACE | awk '{print $3}' | tr -d "."); done
    ncaio · 2009-05-31 16:09:23 12
  • Uncompress a CSS file

    Ever compress a file for the web by replacing all newline characters with nothing so it makes one nice big blob? It is a great idea, however what about when you want to edit that file? ...Serious pain in the butt. I ran into this today in that my only copy of a CSS file was "compressed" with no newlines. I whipped this up and it converted back into nice human readable CSS :-) It could be nicer, but it does the job.


    1
    cat somefile.css | awk '{gsub(/{|}|;/,"&\n"); print}' >> uncompressed.css
    lrvick · 2009-06-02 15:51:51 37
  • Pipe the result of a command to IRC (channel or query)

    command | my_irc Pipe whatever you want to this function, it will, if everything goes well, be redirected to a channel or a user on an IRC server. Please note that : - I am not responsible of flood excesses you might provoke. - that function does not reply to PINGs from the server. That's the reason why I first write in a temporary file. Indeed, I don't want to wait for inputs while being connected to the server. However, according to the configuration of the server and the length of your file, you may timeout before finishing. - Concerning the server, the variable content must be on the form "irc.server.org 6667" (or any other port). If you want to make some tests, you can also create a fake IRC server on "localhost 55555" by using netcat -l -p 55555 - Concerning the target, you can choose a channel (beginning with a '#' like "#chan") or a user (like "user") - The other variables have obvious names. Show Sample Output


    1
    function my_irc { tmp=`mktemp`; cat > $tmp; { echo -e "USER $username x x :$ircname\nNICK $nick\nJOIN $target"; while read line; do echo -e "PRIVMSG $target :$line"; done < $tmp; } | nc $server > /dev/null ; rm $tmp; }
    Josay · 2009-06-11 22:14:48 7
  • Combine two mp3's or more into 1 long mp3

    This just combines multiple mp3's into one mp3 file. Basically it is a easy join for mp3's


    1
    cat 1.mp3 2.mp3 > combined.mp3
    scottix · 2009-07-27 18:39:44 9
  • Make a statistic about the lines of code

    use find to grep all .c files from the target directory, cat them into one stream, then piped to wc to count the lines Show Sample Output


    1
    find . -type f -name "*.c" -exec cat {} \; | wc -l
    foremire · 2009-07-30 10:06:51 14
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Run a command only when load average is below a certain threshold
Good for one off jobs that you want to run at a quiet time. The default threshold is a load average of 0.8 but this can be set using atrun.

Convert spaces in file names to underscores

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

list folders containing less than 2 MB of data
This command will search all subfolders of the current directory and list the names of the folders which contain less than 2 MB of data. I use it to clean up my mp3 archive and to delete the found folders pipe the output to a textfile & run: $ while read -r line; do rm -Rv "$line"; done < textfile

Burn CD/DVD from an iso, eject disc when finished.
cdrecord -scanbus will tell you the (x,y,z) value of your cdr (for example, mine is 3,0,0)

Run a command for blocks of output of another command
The given example collects output of the tail command: Whenever a line is emitted, further lines are collected, until no more output comes for one second. This group of lines is then sent as notification to the user. You can test the example with $ logger "First group"; sleep 1; logger "Second"; logger "group"

ASCII art of yourself
Use libcaca to render ascii chars on the webcam input... or don't.

batch convert Nikon RAW (nef) images to JPG
converts RAW files from a Nikon DSLR to jpg for easy viewing etc. requires ufraw package

a function to create a box of '=' characters around a given string.
First argument: string to put a box around. Second argument: character to use for box (default is '=') Same as command #4948, but shorter, and without the utility function.

Backup all mysql databases to individual files on a remote server
It grabs all the database names granted for the $MYSQLUSER and gzip them to a remote host via SSH.

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