Quick Scripts
Contents |
Introduction
I've always needed a place to store code that I use often, or that I find useful and want to keep just in case. A wiki is perfect for this as it allows me to add quickly, and for others to do the same. I hope this article is of some use to people.
I would like to declare, however, that any code found here is used at the your own risk. I hold no liability, expressed or implied, nor is there warranty of any kind.
Code placed on this page is available under the terms set out at the bottom of this page (namely GNU Free Documentation License 1.2).
MySQL
Create a user
GRANT ALL PRIVILEGES ON *.* TO 'monty'@'localhost' IDENTIFIED BY 'some_pass' WITH GRANT OPTION;
Replace monty with your desired username. *.* means ALL databases and ALL tables, so you may want to change this; the format is DATABASENAME.TABLE
Please note that in never versions of MySQL (5.0.2 and up), it's preferred to use the CREATE USER statement:
CREATE USER 'monty'@'localhost' IDENTIFIED BY 'password'
Backup/Restore
To backup all MySQL databases, run the following:
mysqldump -u root -ppassword -x --all-databases > backup.sql
To restore a MySQL database:
mysql -u root -ppassword < backup.sql
BASH
Find Files Under Current Directory Greater Than 10MB
The following bash one-liner will print all files under the current directory (i.e. in sub-directories too) that are greater that 10MB. The output is piped into du to show actual size in human-readable form:
find . -size +10240k -exec du -h '{}' \;
Convert FLAC to MP3
for file in *.flac; do $(flac -cd "$file" | lame -V 0 - "/tmp/${file%.flac}.mp3"); done
Perl
List files modified today
die "Usage: scriptname.pl directory" if @ARGV < 1;
my $BASE_DATA_DIR = @ARGV[0];
opendir(DIR,$BASE_DATA_DIR) || die("Could not open $BASE_DATA_DIR for reading!");
my @files = readdir(DIR);
use constant DAY_IN_SECONDS => 60 * 60 * 60 * 24;
print_file_list(\@files);
closedir(DIR);
# prints all files in $BASE_DATA_DIR that are modified today
sub print_file_list {
my $file_list = shift;
foreach my $file (@$file_list) {
my $now = time;
my $epoch_yest = $now-DAY_IN_SECONDS;
my $write_secs = (stat("$BASE_DATA_DIR/$file"))[9];
if($write_secs > $epoch_yest) {
# less than a day old, this file was modified today
print "$file was created today";
}
}
}
PHP
List all files in the current directory in a table
Lists all the files in a given directory with modification time and size in KBs (excluding those beginning with '.')
<?php
/*
* Lists the files in the current directory. Safer option than providing the default apache directory listing
*/
$dir = "/some/dir/";?>
<table name="filesTbl" border="1px">
<tr>
<th>Filename</th><th>Modification Date</th><th>Size (KB)</th>
</tr>
<?php
if (is_dir($dir)) {
if ($dh = opendir($dir)) {
while (($file = readdir($dh)) !== false) {
if(strpos($file,".") && $file != "index.php") {
echo "<tr><td><a href=\"$file\">$file</a></td><td>";
echo date("Y-m-d",filemtime("$dir$file")) . "</td><td>";
echo number_format((filesize("$dir$file")/1024),2) . "</td></tr>";
}
}
}
}
?>
</table>
Debian/Ubuntu
List packages that aren't in a repository in sources.list
This is a nice way to list packages that no longer are in the debian repositories (make sure you have installed the apt-show-versions package).
apt-show-versions -b |grep 'No available'
And to print only the package names:
apt-show-versions -b |grep 'No available' | awk '{print $1}'
List uninstalled packages that still have config files
deborphan --find-config
To get rid of those (apt-get remove won't work):
sudo dpkg --purge `deborphan --find-config`
To prevent this happening, provide the '--purge' option when executing 'apt-get remove packagename'. This removes any directories and configuration files related to the package you're removing.
List unused libraries
deborphan
To remove (potentially dangerous, make sure you know what you're doing):
apt-get remove --purge `deborphan`
Check integrity of installed files
You must have the 'debsums' application installed:
#First install it apt-get install debsums #Then create md5sums for packages we don't have info about (just ignore any errors, they are from .debs #that weren't installed with apt) apt-get --reinstall -d install `debsums -l`
To list any changed files (run as root to make sure we have read permissions for all files):
sudo debsums -c
To list changed configuration files:
sudo debsums -se
Listing and Restoring Installed Packages
The following set of commands are useful for backup and restoring a server's packages when something's gone sour:
dpkg --get-selections > /etc/package.selections # save the list of installed packages
To restore the installed packages at a later date, or on a newly installed Debian machine:
dpkg --set-selections < /etc/package.selections && apt-get dselect-upgrade
Thanks to Keith Edmunds of the Hampshire Linux User Group for this one.
Reinstall config files
To reinstall config files, delete the config file you want to reinstall, then do the following
apt-get -o DPkg::Options::="--force-confmiss" --reinstall install PACKAGE_NAME
where PACKAGE_NAME is the name of the package that contains the config file you want to replace
