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 40
  • 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 10:52:35 233
  • 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 07:16:58 107
  • 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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Determine next available UID
better with accounts on ldap

connect via ssh using mac address
Connect to a machine running ssh using mac address by using the "arp" command

See where a shortened url takes you before click

Benchmark SQL Query
Benchmark a SQL query against MySQL Server. The example runs the query 10 times, and you get the average runtime in the output. To ensure that the query does not get cached, use `RESET QUERY CACHE;` on top in the query file.

Find last modified files in a directory and its subdirectories
Goes through all files in the directory specified, uses `stat` to print out last modification time, then sorts numerically in reverse, then uses cut to remove the modified epoch timestamp and finally head to only output the last 10 modified files. Note that on a Mac `stat` won't work like this, you'll need to use either: $ find . -type f -print0 | xargs -0 stat -f '%m%t%Sm %12z %N' | sort -nr | cut -f2- | head or alternatively do a `brew install coreutils` and then replace `stat` with `gstat` in the original command.

Connect to TCP port 5000, transfer data and close connexion.
With no '-q 0' switch, nc simply waits, and whatever awaits the data hangs.

Easy and fast access to often executed commands that are very long and complex.
When using reverse-i-search you have to type some part of the command that you want to retrieve. However, if the command is very complex it might be difficult to recall the parts that will uniquely identify this command. Using the above trick it's possible to label your commands and access them easily by pressing ^R and typing the label (should be short and descriptive). UPDATE: One might suggest using aliases. But in that case it would be difficult to change some parts of the command (such as options, file/directory names, etc).

Show changed files, ignoring permission, date and whitespace changes
Only shows files with actual changes to text (excluding whitespace). Useful if you've messed up permissions or transferred in files from windows or something like that, so that you can get a list of changed files, and clean up the rest.

statistics in one line
In this example, file contains five columns where first column is text. Variance is calculated for columns 2 - 5 by using perl module Statistics::Descriptive. There are many more statistical functions available in the module.

A snooze button for xmms2 alarm clock
you can also run "xmms2 pause & at now +5min

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