Commands using unset (14)

  • disable history for current shell session

    this will cause any commands that you have executed in the current shell session to not be written in your bash_history file upon logout


    18
    unset HISTFILE
    grokskookum · 2009-05-20 14:46:18 20
  • Prevent shell autologout

    Unset TMOUT or set it to 0 in order to prevent shell autologout. TMOUT is the number of seconds after which the present shell will be killed if it has been idle for that long.


    7
    unset TMOUT
    sharfah · 2009-05-20 14:57:50 12
  • Don't save commands in bash history (only for current session)

    Unsetting HISTFILE avoid getting current session history list saved.


    6
    unset HISTFILE
    Delian · 2010-11-15 09:16:11 7
  • no more line wrapping in your terminal

    works on all unices. Show Sample Output


    4
    function nowrap { export COLS=`tput cols` ; cut -c-$COLS ; unset COLS ; }
    mobidyc · 2009-09-11 15:07:00 13
  • Make changes in .bashrc immediately available

    Simply sourcing .bashrc does not function correctly when you edit it and change an alias for a function or the other way round with the *same name*. I therefor use this function. Prior to re-sourcing .bashrc it unsets all aliases and functions.


    4
    bashrc-reload() { builtin unalias -a; builtin unset -f $(builtin declare -F | sed 's/^.*declare[[:blank:]]\+-f[[:blank:]]\+//'); . ~/.bashrc; }
    Xk2c · 2014-03-02 14:24:18 9
  • 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 #4962, cleaned up, shortened, and more efficient. Now a ' * ' can be used as the box character, and the variables get unset so they don't mess with anything else you might have. They marked c++ as a function for this command, but I'm not sure why. Must be a bug. Show Sample Output


    2
    box(){ c=${2-=}; l=$c$c${1//?/$c}$c$c; echo -e "$l\n$c $1 $c\n$l"; unset c l;}
    mightybs · 2010-02-26 17:14:52 3
  • Directory bookmarks

    pushd and popd are your friends, but sometimes they're just incompatible with the way one works... Two shell functions: bm bookmarkname - "bookmarks" the current directory, just 'cd $BMbookmarkname' to return to it. forget bookmarkname - unsets the 'bookmarkname' variable. It isn't mandatory, they cease to exist when the session ends. Show Sample Output


    2
    bm() { export BM${1?"bookmark name missing"}="$PWD" ; }; forget() { unset BM${1?"bookmark name missing"} ; }
    unefunge · 2010-11-19 12:15:11 18
  • Drop all tables from a database, without deleting it


    1
    MYSQL="mysql -h HOST -u USERNAME -pPASSWORD -D DB_NAME" ; $MYSQL -BNe "show tables" | awk '{print "set foreign_key_checks=0; drop table `" $1 "`;"}' | $MYSQL unset MYSQL
    gadget00 · 2009-12-01 17:42:38 7
  • zsh suffix to inform you about long command ending

    make, find and a lot of other programs can take a lot of time. And can do not. Supppose you write a long, complicated command and wonder if it will be done in 3 seconds or 20 minutes. Just add "R" (without quotes) suffix to it and you can do other things: zsh will inform you when you can see the results. You can replace zenity with other X Window dialogs program.


    1
    alias -g R=' &; jobs | tail -1 | read A0 A1 A2 cmd; echo "running $cmd"; fg "$cmd"; zenity --info --text "$cmd done"; unset A0 A1 A2 cmd'
    pipeliner · 2010-12-13 17:44:36 2
  • generate random ascii shape(no x11 needed!)

    Show Sample Output


    1
    echo 'set term dumb; unset border; unset xtics; unset ytics; p "< seq 10 | shuf" u 1:(rand(0)) w l notitle' | gnuplot
    kev · 2011-11-30 02:08:53 4
  • dont log current session to history


    1
    unset HISTFILE
    aysadk · 2017-09-01 09:12:11 19
  • Play a random .avi file from a media tree

    unsets variables used by the one-liner sets up the IFS bash variable to not be affected by whitespace and disables extra glob expansion uses read to slurp the results of the find command into an array selects an element of the array at random to be passed as an argument to mplayer


    0
    unset files i; set -f; O=$IFS; while IFS= read -r -d $'\0' files[i++]; do :; done < <(find . -name '*.avi' -print0) && IFS=$O; set +f && echo "Running: mplayer \"${files[ $(( $RANDOM % ${#files[@]} )) ]}\""
    DEinspanjer · 2009-02-18 16:53:57 6
  • Find Man pages for everything in your $PATH

    If I type 'man something', I want it to find the manpage in the same order as my PATH. You can add something like this to your .bashrc # # Add my MacPorts, my personal utilities and my company utilities to my PATH. export PATH=$PATH:/opt/local/bin:$HOME/bin:/our_company_utils/bin/ # Now set the manpath based on the PATH, after man(1) parses man.conf # - No need to modify man.conf or manually modify MANPATH_MAP # - Works on Linux, FreeBSD & Darwin, unlike /etc/manpaths.d/ # Must unset MANPATH first. MANPATH is set on some systems automatically (Mac), # which causes manpath to ignore the values of PATH like /opt/local/bin (MacPorts). # Also MANPATH may be deprecated. See "SEARCH PATH FOR MANUAL PAGES" in man(1) unset MANPATH # manpath acts differently on Solaris, FreeBSD, MacOSX & GNU. This works everywhere. manpath >/dev/null # Note that MacOSX, FreeBSD & Linux have fancier ways to do some of this. (e.g. 'man --path' or 'man -q'), but this command is more universal and should work everywhere. Show Sample Output


    0
    unset MANPATH; manpath >/dev/null
    StefanLasiewski · 2010-07-02 19:45:27 3
  • Do mathematical operation on every line of a given file for the first value found to be replaced (other lines stay untouched)

    The given file may contain any kind of characters. This is compatible for most simple mathematical operation. For the first number found, it will be replaced by the result of a factor operation of 1000. To change the filename or multiplactor or number regular expression, change the first fixed values. Show Sample Output


    0
    n=1000;f="test.csv";r='([0-9]+.{0,1}[0-9]*)';echo -n "" > new_${f};cat $f | while read l;do val=`echo $l | egrep -o $r` ; if [ ! -z $val ];then newval=`echo $val \* $n | bc -l`;l=`echo $l | sed "s/$val/$newval/"`;fi;echo $l >> new_${f};unset val;done
    s333 · 2017-04-26 18:04:07 19

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Transfer SSH public key to another machine in one step
This command sequence allows simple setup of (gasp!) password-less SSH logins. Be careful, as if you already have an SSH keypair in your ~/.ssh directory on the local machine, there is a possibility ssh-keygen may overwrite them. ssh-copy-id copies the public key to the remote host and appends it to the remote account's ~/.ssh/authorized_keys file. When trying ssh, if you used no passphrase for your key, the remote shell appears soon after invoking ssh user@host.

Write comments to your history.
A null operation with the name 'comment', allowing comments to be written to HISTFILE. Prepending '#' to a command will *not* write the command to the history file, although it will be available for the current session, thus '#' is not useful for keeping track of comments past the current session.

Read aloud a text file in Mac OS X

Count number of files in a directory
Just want to post a Perl alternative. Does not count hidden files ('.' ones).

Download all PDFs from an authenificated website
Replace *** with the appropiate values

Multi-thread any command
For instance: $ find . -type f -name '*.wav' -print0 |xargs -0 -P 3 -n 1 flac -V8 will encode all .wav files into FLAC in parallel. Explanation of xargs flags: -P [max-procs]: Max number of invocations to run at once. Set to 0 to run all at once [potentially dangerous re: excessive RAM usage]. -n [max-args]: Max number of arguments from the list to send to each invocation. -0: Stdin is a null-terminated list. I use xargs to build parallel-processing frameworks into my scripts like the one here: http://pastebin.com/1GvcifYa

disable caps lock
a quick one-line way to disable caps lock while running X.

Get a qrcode for a given string

Setting reserved blocks percentage to 1%
According to tune2fs manual, reserved blocks are designed to keep your system from failing when you run out of space. Its reserves space for privileged processes such as daemons (like syslogd, for ex.) and other root level processes; also the reserved space can prevent the filesystem from fragmenting as it fills up. By default this is 5% regardless of the size of the partition. http://www.ducea.com/2008/03/04/ext3-reserved-blocks-percentage/

Show apps that use internet connection at the moment.
show only the name of the apps that are using internet

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