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This command will tell you the 20 biggest directories starting from your working directory and skips directories on other filesystems. Useful for resolving disk space issues.
If you need to print some portion of a huge file, let's say you want to print from line 200 to 300, you can use this command to print the line from LINE1 to LINE2 of file FILE.
The pinfo package makes info pages much more bearable. It is a ncurses-based POSIX utility for viewing info and man pages using lynx style keyboard shortcuts and rendering. Links are highlighted blue, the current location of your cursor is red. Navigating and searching are easy. Worth the install.
By time thumbnail images in ~/thumbnails take up too much space, this command will help deleting old ones.
Find options explained:
-type f : find files only, not directories
-atime +30 : last accessed more than 30 days ago
An improved version of http://www.commandlinefu.com/commands/view/1772/simple-countdown-from-a-given-date that uses Perl to pretty-print the output. Note that the GNU-style '--no-title' option has been replaced by its one-letter counterpart '-t'.
If (when) you forget to "svn rm" files from your repository, use this to let your repository know you want those files gone. Of course this works with adding and reverting too.
Extremely useful to maintain backups if you're using Dropbox. This mirrors the entire directory structure and places symlinks in each to the original file. Instead of copying over the data again to the ~/Dropbox folder creating a symbolic link tree is much more sensible in terms of space usage.
This has to be supplemented by another script that removes dead symlinks in the Dropbox folder which point to files that have been moved/removed.
find -L ./ -type l -delete
And then removing empty directories
find ./ -type d -exec rmdir 2>/dev/null {} \;
**Actually after some finding I found lndir which creates symbolic trees but it wasn't in the Arch repos so.. ;)
This requires that your sudo not prompt for a password, as sftp cannot allocate the terminal necessary to ask.
Might be more useful if you were able to print it in Days HH:MM:SS format as:
perl -e '@p=gmtime(234234);printf("%d Days %02d:%02d:%02ds\n",@p[7,2,1,0]);'
But I'm not exactly sure how to replace the 234234 with the output of the countdown time. (Having some problems with nested quoting/command substitution). Help would be appreciated :)
Several times, I find myself hitting my up arrow, and changing the search term. Unfortunately, I find myself wasting too much time typing:
grep kernel /var/log/messages
Redirecting STDIN allows me to put the search term at the end so I less cursor movement to change what I'm searching for:
< /var/log/messages grep kernel
If you're using the emacs keyboard binding, then after you press your up arrow, press CTRL+w to erase the word.
If this has already been submitted, I couldn't find it with the search utility.
Here is a command line to run on your server if you think your server is under attack. It prints our a list of open connections to your server and sorts them by amount.
BSD Version:
netstat -na |awk '{print $5}' |cut -d "." -f1,2,3,4 |sort |uniq -c |sort -nr
This command is useful when you want to install the same packages on another fresh OS install for example. To do that, use:
sudo dpkg --set-selections < LIST_FILE
Update a Mandriva Linux system with any pending updates.
This command needs to be run with root privilege.
Using the "--force" option answers "yes" to any interactive prompts
thus allowing the updates to be left unattended to completion.
NB if there is an update for glibc and/or a new kernel then the system
would need to be rebooted for these to take effect.
A prerequisite for running "urpmi --auto-update" is to have correctly defined
urpmi media sources (which can be done by visiting http://easyurpmi.zarb.org/).
If there are no new updates the the message "Packages are up to date" is shown.
I find this terribly useful for grepping through a file, looking for just a block of text. There's "grep -A # pattern file.txt" to see a specific number of lines following your pattern, but what if you want to see the whole block? Say, the output of "dmidecode" (as root):
dmidecode | awk '/Battery/,/^$/'
Will show me everything following the battery block up to the next block of text. Again, I find this extremely useful when I want to see whole blocks of text based on a pattern, and I don't care to see the rest of the data in output. This could be used against the '/etc/securetty/user' file on Unix to find the block of a specific user. It could be used against VirtualHosts or Directories on Apache to find specific definitions. The scenarios go on for any text formatted in a block fashion. Very handy.
Packages: gmailfs fuse-utils libfuse2 gvfs-fuse
Config files: /etc/gmailfs/gmailfs.conf; ~/.gmailfs.conf (make a copy from the another one)
Unmount:
fusermount -u /mount/path/
/etc/fstab (Optional):
none /mount/path/ gmailfs
noauto,user[,username=USERNAME,password=PASSWORD,fsname=VOLUME] 0 0
NOTES:
- The options between [] are optional since they already setuped on the config files.
- The '-p' flag shows a prompt for the password entry.
- It's necessary to add the user to the 'fuse' group. You can do that with:
sudo chgrp fuse /dev/fuse
and
sudo usermod -a -G fuse USER
- The volume name is not needed but highly recommended to avoid file corruption. Also choose a non-trivial name.
- Google doesn't approve the use of Gmail account other than e-mail purposes. So, I recommend the creation of a new account for this.
Perform a dns zone transfer (if is allowed on target dns server) and print result.
See: "man pwgen" for full details.
Some Linux distros may not have pwgen included in the base distribution
so you maye have to install it (eg in Mandriva Linux: "urpmi pwgen").