Commands by b_t (21)

  • Remove orphaned dependencies on Arch

    -Qdt Lists dependencies/packages which are no longer required by any packages -q Output only package name (not the version number) -R Remove package(s) Rest is self-explanatory. I just started out with Arch - so if there is any better/standard method to achieve the same - please suggest.


    4
    pacman -Qdt -q | xargs pacman --noconfirm -R
    b_t · 2014-02-27 05:17:57 5
  • Show complete URL in netstat output

    The -W switch of netstat makes it print complete URL of the connections, which otherwise by default is truncated to fit its default column size. Now to compensate for irregular column sizes, pipe the output to column (-t switch of column prints in tabular form). The only downside to this part is that the very first row, the header, goes pear shape. Show Sample Output


    6
    netstat -tup -W | column -t
    b_t · 2014-01-08 22:39:01 5
  • sort monthwise

    sort command can sort month-wise (first three letters of each month). See the sample output for clarification. Sorting Stable ? NO. Take note if that matters to you. Sample output suggests that sort performs unstable sorting (see the relative order of two 'feb' entries). Show Sample Output


    2
    sort -M filename
    b_t · 2011-12-10 12:50:30 185
  • Instantly load bash history of one shell into another running shell

    By default bash history of a shell is appended (appended on Ubuntu by default: Look for 'shopt -s histappend' in ~/.bashrc) to history file only after that shell exits. Although after having written to the history file, other running shells do *not* inherit that history - only newly launched shells do. This pair of commands alleviate that. Show Sample Output


    10
    $ history -a #in one shell , and $ history -r #in another running shell
    b_t · 2011-11-05 01:19:30 5
  • Find out which debian package a command (executable) belongs to on debian-based distros

    This revision to my command (command #8851) was called for when it failed to find the parent package of 'rlogin', which is really a deep symbolic link to /usr/bin/ssh. This revision fixes this newfound issue, while ensuring fixes of other older issues work too. Show Sample Output


    7
    function whichpkg() { readlink -f "$(which $1)" | xargs --no-run-if-empty dpkg -S; }
    b_t · 2011-10-28 02:53:19 2
  • Verify/edit bash history command before executing it

    Bash history commands are those that begin with the character ! (eg. the most popular 'sudo !!' Explained here => http://www.commandlinefu.com/commands/view/13). By default bash immediately executes the history command. Setting this shell option will make bash first allow you to verify/edit an history command before executing it. To set this option permanently, put this command in ~/.profile or ~/.bashrc file. To unset this option issue following command. shopt -u histverify Show Sample Output


    14
    shopt -s histverify
    b_t · 2011-10-27 00:33:34 7
  • Find the package a command belongs to on debian-based distros

    Advanced revision to the command 8776 . This revision follows symbolic links. The quotation-marks surrounding $(which $1) allows for graceful handling of errors ( ie. readlink does not complain incase 'which' command generates (null) output) Show Sample Output


    1
    whichpkg () { dpkg -S $1 | egrep -w $(readlink -f "$(which $1)")$; }
    b_t · 2011-07-17 13:39:56 2
  • A command's package details

    This version builds on my command 8776 (Find the package a command belongs to on debian-based distros). So if you use that command to find package name then you could alternatively use following for package summary: function summpkg { dpkg -s $(whichpkg $1 | awk -F: '{print $1}'); } Show Sample Output


    0
    function summpkg { dpkg -s $(dpkg -S $1 | egrep -w $(which $1)$ | awk -F: '{print $1}') ; }
    b_t · 2011-07-05 23:06:37 2
  • Find the package a command belongs to on debian-based distros

    Similar to command 7822, but handles errors gracefully. Show Sample Output


    0
    function whichpkg { dpkg -S $1 | egrep -w $(which $1)$; }
    b_t · 2011-07-05 22:56:48 2
  • Get all files of particular type (say, PDF) listed on some wegpage (say, example.com)

    This example command fetches 'example.com' webpage and then fetches+saves all PDF files listed (linked to) on that webpage. [*Note: of course there are no PDFs on example.com. This is just an example]


    1
    curl -s http://example.com | grep -o -P "<a.*href.*>" | grep -o "http.*.pdf" | xargs -d"\n" -n1 wget -c
    b_t · 2011-06-09 14:42:46 3
  • Debug your makefile

    Say your dependencies specified in your Makefile (or dates on your source files) is causing 'make' to skip some source-files (that it should not) or on the other other end, if it is causing make to always build some source-files regardless of dates of target, then above command is handy to find out what 'make' thinks of your date v/s target date-wise or what dependencies are in make's view-point. The egrep part removes the extra noise, that you might want to avoid. Show Sample Output


    1
    make -d | egrep --color -i '(considering|older|newer|remake)'
    b_t · 2011-06-03 01:55:08 52
  • Deleting a remote git branch (say, by name 'featureless')

    This will delete the branch 'featureless' on the origin remote. Do not forget to delete the branch locally using: git branch -d featureless 'I got it here'-credit: http://gitready.com/beginner/2009/02/02/push-and-delete-branches.html I duplicated here incase you stumbled here first. Show Sample Output


    -1
    git push origin :featureless
    b_t · 2011-06-02 14:53:31 2
  • List only those files that has all uppercase letters in their names (e.g. README)

    Some source package have many 'README' kind of files, among many other regular files/directories. This command could be useful when one wants to list only 'README' kind of files among jungle of other files. (e.g. I came across this situation after downloading source for module-init-tools) Warning: This command would miss a file like => README.1 (or one with spaces in-between) Corrections welcome. Show Sample Output


    0
    ls | grep '^[A-Z0-9]*$'
    b_t · 2010-12-19 21:45:53 3
  • Signals list by NUMBER and NAME

    This command seems to achieve the similar/same goal.


    7
    kill -l
    b_t · 2010-11-17 23:48:51 4
  • Ranking of the most frequently used commands

    Your version works fine except for someone who's interested in commands 'sudo' was prefixed to i.e. in your command, use of sudo appears as number of times sudo was used. Slight variation in my command peeks into what commands sudo was used for and counts the command (ignores 'sudo')


    0
    history | awk '{print $2,$3}' | sed s/sudo// | awk '{print $1}' | awk 'BEGIN {FS="|"}{print $1}' | sort | uniq -c | sort -n | tail | sort -nr
    b_t · 2010-11-17 12:15:04 2
  • List only executables installed by a debian package

    I wanted to view only executables installed by a package. This seemed to work. There's got to be easier way, please share. Note: (1) Replace iptables with the package name of your interest (2) The command will trash any existing environment variable named 'lst' (3) Instead if you are interested in viewing just .ko or .so files installed by this package, then that would be easy: $ dpkg -L iptables | grep "\.[sk]o$" Show Sample Output


    1
    lst=`dpkg -L iptables` ; for f in $lst; do if [ -x $f ] && [ ! -d $f ] ; then echo $f; fi; done;
    b_t · 2010-10-30 14:47:45 4
  • commandline dictionary

    Note: 1) Replace 'wonder' with any word you looking the meaning for in the above example 2) Need to install these packages: wordnet & wordnet-base (latter should be automatically installed because of dependency) 3) Combined size of packages is about 30MB on my old ubuntu system (I find it worth it) Show Sample Output


    3
    wn wonder -over
    b_t · 2010-10-05 13:56:06 32
  • sudo for launching gui apps in background

    Need package: gksu Note: Launching gui app in background that needs sudo, won't work great with our old friendly style of launching: sudo gedit /etc/passwd & because this would put sudo in background ! Using gksudo as demonstrated, would popup a gui sudo window. May be this is a common knowledge, but not knowing this frustrated me during my newbie year.


    1
    gksudo gedit /etc/passwd &
    b_t · 2010-10-05 13:11:04 6
  • Make sudo forget password instantly

    By default sudo 'remembers' password for a few minutes, so that you do not need to re-enter password for a series of sudo commands that might follow within a short time duration. However, sometime you might want sudo to instantly 'forget' the password. (Next sudo command will need you to reenter the password) Credit: I first learned this while listening to one of the 'tuxradar' podcast. Show Sample Output


    17
    sudo -K
    b_t · 2010-10-05 12:44:26 3
  • Remind yourself every 15 minutes (repeated reminders)

    Note: 1) -n option of watch accepts seconds 2) -t option of notify-send accepts milliseconds 3) All quotes stated in the given example are required if notification message is more than a word. 4) I couldn't get this to run in background (use of & at the end fails). Any suggestions/improvements welcome.


    1
    watch -n 900 "notify-send -t 10000 'Look away. Rest your eyes'"
    b_t · 2010-10-05 09:39:31 5
  • Sort on multiple dis-contiguous keys/fields (can even specify key number/field from the end)

    Notes: 1) -n-1 means sort key is the last field 2) -l is important if each separate record is on a new line (usually so for text files) 3) -j tells msort not to create log file (msort.log) in the working directory 4) may need to install msort package. 5) msort does lot more. Check man msort Show Sample Output


    4
    file /bin/* | msort -j -l -n-1 -n2 2> /dev/null
    b_t · 2010-10-05 00:37:33 3

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Alias TAIL for automatic smart output
Run the alias command, then issue $ps aux | tail and resize your terminal window (putty/console/hyperterm/xterm/etc) then issue the same command and you'll understand. $ ${LINES:-`tput lines 2>/dev/null||echo -n 12`} Insructs the shell that if LINES is not set or null to use the output from `tput lines` ( ncurses based terminal access ) to get the number of lines in your terminal. But furthermore, in case that doesn't work either, it will default to using the default of 80. The default for TAIL is to output the last 10 lines, this alias changes the default to output the last x lines instead, where x is the number of lines currently displayed on your terminal - 7. The -7 is there so that the top line displayed is the command you ran that used TAIL, ie the prompt. Depending on whether your PS1 and/or PROMPT_COMMAND output more than 1 line (mine is 3) you will want to increase from -2. So with my prompt being the following, I need -7, or - 5 if I only want to display the commandline at the top. ( http://www.askapache.com/linux/bash-power-prompt.html ) 275MB/748MB [7995:7993 - 0:186] 06:26:49 Thu Apr 08 [askapache@n1-backbone5:/dev/pts/0 +1] ~ $ In most shells the LINES variable is created automatically at login and updated when the terminal is resized (28 linux, 23/20 others for SIGWINCH) to contain the number of vertical lines that can fit in your terminal window. Because the alias doesn't hard-code the current LINES but relys on the $LINES variable, this is a dynamic alias that will always work on a tty device.

Place the argument of the most recent command on the shell
This works if your terminal is in Vi mode

Apply an xdelta patch to a file
xdelta is a command line program for delta encoding, which generates the difference between two files. This is similar to diff and patch, but it is targeted for binary files and does not generate human readable output. http://xdelta.org/

Processes by CPU usage

Log the current memory statistics frequently to syslog
Uses logger in a while loop to log memory statistics frequently into the local syslog server.

Convert seconds into minutes and seconds
This is a very simple way to input a large number of seconds and get a more useful value in minutes and seconds.

pngcrush all .png files in the directory
Find all pngs in directory structure and pngcrush them, none destructive. You can just remove the "{}.crush" part if you want destructive.

Change the ownership of all files owned by one user.
Finds all files in /home owned by UID 1056 and changes to 2056.

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"

Rename files in batch

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