Commands by knoppix5 (60)

  • Alternative if "Lazy unmount" (umount -l) doesn't obey. Alternative for NFS: umount -f /media/sdb1 Use with caution: forcing to unmount a busy partition can cause data loss!


    1
    fuser -km /media/sdb1
    knoppix5 · 2012-02-27 13:41:05 0
  • works in bash Show Sample Output


    8
    grep $'\t' sample.txt
    knoppix5 · 2012-02-21 10:54:56 0
  • Output of this command is the difference of recursive file lists in two directories (very quick!). To view differences in content of files too, use the command submitted by mariusbutuc (very slow!): diff -rq path_to_dir1 path_to_dir2 Show Sample Output


    3
    diff --suppress-common-lines -y <(cd path_to_dir1; find .|sort) <(cd path_to_dir2; find .|sort)
    knoppix5 · 2012-02-13 12:49:33 2
  • Every 20 minutes test if host with IP 192.168.0.14 is 'dead' or not reachable. The line should be put in your crontab file.


    -4
    10,30,50 * * * * ping -q -c1 -w3 192.168.0.14 | grep '1 received' - || mail -ne -s'Host 192.168.0.14 not reachable' [email protected]
    knoppix5 · 2012-02-06 10:42:46 0
  • Every 20 minutes ping host with IP address 192.168.0.14. If it's not 'alive' or not reachable, then display something eye-catching (here xeyes) on the desktop. Hint for newbies: edit crontab with crontab -e


    -2
    10,30,50 * * * * ping -q -c1 -w3 192.168.0.14 | grep '1 received' - || env DISPLAY=:0 xeyes
    knoppix5 · 2012-02-06 09:40:11 0
  • You can compare directories on two different remote hosts as well: diff -y <(ssh [email protected] find /boot|sort) <(ssh [email protected] find /boot|sort) To avoid password-prompt on remote host just generate the rsa key locally and copy it to remote host: ssh-keygen -t rsa then ssh [email protected] "mkdir .ssh" then scp .ssh/id_rsa.pub [email protected]:; .ssh/authorized_keys2


    3
    diff -y <(ssh [email protected] find /boot|sort) <(find /boot|sort)
    knoppix5 · 2012-01-31 15:04:30 0
  • If any changes have been made to the package while it was unpacked (ie, conffiles files in /etc modi‐fied), the new package will inherit the changes. This way you can make it easy to copy packages from one computer to another, or to recreate packages that are installed on your system, but no longer available elsewhere. Note: dpkg-repack will place the created package in the current directory. Show Sample Output


    8
    dpkg-repack firefox
    knoppix5 · 2012-01-13 11:47:40 2
  • This command does the following: - converts any sequence of multiple spaces/tabs to one space only - completely removes any space(s)/tab(s) at the end of each line (If spaces and tabs are mixed in a sequence i.e. [tab][tab][space][tab], you have to execute this command twice!) Show Sample Output


    -4
    sed -i "s/\(\x09\{1,\}\)\|\( \{1,\}\)/ /g;s/\(\x09\{1,\}$\)\|\( \{1,\}$\)//g" brisati.txt
    knoppix5 · 2011-12-12 10:24:03 3
  • Schematics: command [options] [paste your variable here] parameter command [options] [paste entire column of variables here] parameter ... (hard-code command "c" and parameter "e" according to your wishes: in example shown command = "cp -a" and parameter = "~") Features: - Quick exchange only variable part of a long command line - Make variable part to be an entire column of data (i.e. file list) - Full control while processing every single item Hints: Paste column of data from anywhere. I.e. utilize the Block Select Mode to drag, select and copy columns (In KDE Konsole with Ctrl+Alt pressed, or only Ctrl pressed in GNOME Terminal respectively). Disadvantages: You can paste only one single variable in a row. If there are more space separated variables in a row only first one will be processed, but you can arrange your variables in a column instead. To transpose rows to columns or vice versa look at Linux manual pages for 'cut' and 'paste'. TODO: - add edit mode to vary command "c" and parameter "e" on the fly - add one edit mode more to handle every list item different - add y/n/a (=All) instead of only y(=default)/n to allowed answers Disclaimer: The code is not optimized, only the basic idea is presented here. It's up to you to shorten code or extend the functionality. Show Sample Output


    -1
    c="cp -a";e="~";echo -e "\npaste\n";i=0;k="1"; while [[ "$k" != "" ]]; do read -a k;r[i]=$k;((i++));done;i=0;while :;do t=${r[i]};[ "$t" == "" ] && break; g=$(echo $c ${r[i]} $e);echo -e $g "\ny/n?";read y;[ "$y" != "n" ] && eval $g;((i++));done
    knoppix5 · 2011-12-04 12:45:44 0
  • This alias is meant to append n (here is n=10) most recently used cd commands to the bottom of history file. This way you can easily change to one of previous visited directories simply by hitting 1-10 times arrow up key. Hint: You can make more aliases implying the same rule for any set of frequently used long and complex commands like: mkisof, rdesktop, gpg...


    1
    alias cdd="history -a && grep '^ *[0-9]* *cd ' ~/.bash_history| tail -10 >>~/.bash_history && history -r ~/.bash_history"
    knoppix5 · 2011-07-13 09:44:16 0
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Mute speakers after an hour
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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"

Scan for new SCSI devices
Issues a scan command on the given scsi host adapter (ex. a fibre channel adapter, in the example above on host0). Output can be watched in the messages log or in "dmesg"

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"

Printable random characters
Reads psuedorandom bytes from /dev/urandom, filtering out non-printable ones. Other character classes can be used, such as [:alpha:], [:digit:] and [:alnum:]. To get a string of 10 lowercase letters: $ tr -dc '[:lower:]' < /dev/urandom | head -c 10

Simplest way to get size (in bytes) of a file

Match a URL
For the record: I didn't build this. Just shared what I found that worked. Apologies to the original author! I decided I should fix the case where http://example.com is not matched for the next time I need this. So I read rfc1035 and formalized the host name regex. If anyone finds any more holes, please comment.

Change mysql prompt to be more verbose
You can put this into your shell sourced file like .bashrc or .zshrc to have a different mysql prompt. See http://dev.mysql.com/doc/refman/5.1/de/mysql-commands.html for more informations. Beware that currently with mysql 5.5 the seconds are buggy and won't be displayed if you put this into a .cnf file. With the enironment variable this will work.

Rip a video for archiving, from any site
Download video files from a bunch of sites (here is a list https://rg3.github.io/youtube-dl/supportedsites.html). The options say: base filename on title, ignores errors and continue partial downloads. Also, stores some metadata into a .json file plz. Paste youtube users and playlists for extra fun. Protip: git-annex loves these files

Are the two lines anagrams?
This works by reading in two lines of input, turning each into a list of one-character matches that are sorted and compared.


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