: [arguments]
	No effect; the command does nothing beyond expanding arguments and performing any specified redirections.  A zero exit code is returned.

• For example, if you want to avoid using a negation (for fear of history expansion still being on by default on a interactive bash or wanting to support ancient shells), you cannot simply write

  if conditon ; then
  	# this will be an error
  else
  	echo condition is false
  fi
  

  but need some command there, for which the colon can be used:

  if conditon ; then
  	: # nothing to do in this case
  else
  	echo condition is false
  fi
  

  To confuse your reader, you can use the fact that the colon ignores it's arguments and you only have normal words there:

  if conditon ; then
  	: nothing to do in this case # <- this works but is not good style
  else
  	echo condition is false
  fi
  

  though I strongly recommend against it (exercise: why did I use a # there for my remark?).
• This of course also works in other cases:

  while processnext ; do
  	:
  done
  

• The ability to ignore the actual arguments (but still processing them as with every command that ignores it arguments) can also be used, like in:

  : $ VARNAME:=default 
  

  which sets VARNAME to a default if unset or empty. (One could also use that the first time it is used, or $ VARNAME:-default everywhere, but this can be more readable).
• In other cases you do not strictly need a command, but using the colon can clear things up, like creating or truncating a file using a redirection:

  : > /path/to/file
  

• misuing it for comments:

  : ====== here
  

  While it has the advantage of also showing up in -x output, the to be expected confusion of the reader and the danger of using any shell active character makes this general a bad idea.
• As it practically the same as true it can be used as a shorter form of true. Given that true is more readable that is a bad idea. (At least it isn't as evil as using the empty string to denote true.)

  # bad style!
  if condition ; then doit= ; doit2=: ; else doit=false ; doit2=false ; fi
  if $doit ; then echo condition true ; fi
  if $doit2 && true ; then echo condition true ; fi
  

• Another way to scare people:

  ignoreornot=
  $ignoreornot echo This you can see.
  ignoreornot=:
  $ignoreornot echo This you cannot see.
  

  While it works, I recommend against it: Easily confusing and any > in there or $(...) will likely rain harvoc over you.
• Last and least, one can shadow the built-in colon with a different one. Only useful for obfuscation, and thus likely always evil. :() :&: ;: anyone?

when HTTP_REQUEST  
    if   [HTTP::cookie "JSESSIONID"] ne ""  
        persist uie [string tolower [HTTP::cookie "JSESSIONID"]] 1800 
     
 
when HTTP_RESPONSE  
    if   [HTTP::cookie "JSESSIONID"] ne ""  
        persist add uie [string tolower [HTTP::cookie "JSESSIONID"]] 1800
     
 

1. Can we maybe improve the change process for the balancer to handle a mixed traffic scenario?
2. Do we need monitoring to monitor the balancing of requests?
3. Is it a wise idea to mix machine2machine and user2machine traffic on the same port?
4. Should we maybe, if we seperate properly, place management applications on a different system?
5. Is our documentation sufficient?

• Hot Knife: This was the song I was introduced to her with. And I love the kettledrum rhythm and sound.
• Criminal: Definitely a different sound, but it was the song that won her a Grammy.
• Not About Love: Such a lovely composition. I do love the way she plays the piano.

/music permanent link Comments: 0 Flattr this

testvm :: Host
testvm = host "testvm.kitenet.net"
        & os (System (Debian Unstable) "amd64")
        & OS.cleanInstallOnce (OS.Confirmed "testvm.kitenet.net")
                 onChange  propertyList "fixing up after clean install"
                        [ User.shadowConfig True
                        , OS.preserveRootSshAuthorized
                        , OS.preserveResolvConf
                        , Apt.update
                        , Grub.boots "/dev/sda"
                                 requires  Grub.installed Grub.PC
                        ]
        & Hostname.sane
        & Hostname.searchDomain
        & Apt.installed ["linux-image-amd64"]
        & Apt.installed ["ssh"]
        & User.hasSomePassword "root"

• Technology is so much better now. I can spin up cloud VMs for testing in seconds; I use VirtualBox to restore a system from a snapshot. So testing is much much easier. The first work on d-i was done by booting real machines, and for a while I was booting them using floppies.
• Propellor doesn't have a user interface. The best part of d-i is preseeding, but that was mostly an accident; when I started developing d-i the first thing I wrote was main-menu (which is invisible 99.9% of the time) and we had to develop cdebconf, and tons of other UI. Probably 90% of d-i work involves the UI. Jettisoning the UI entirely thus speeds up development enormously. And propellor's configuration file blows d-i preseeding out of the water in expressiveness and flexability.
• Propellor has a much more principled design and implementation. Separating things into Properties, which are composable and reusable gives enormous leverage. Strong type checking and a powerful programming language make it much easier to develop than d-i's mess of shell scripts calling underpowered busybox commands etc. Properties often Just Work the first time they're tested.
• No separate runtime. d-i runs in its own environment, which is really a little custom linux distribution. Developing linux distributions is hard. Propellor drops into a live system and runs there. So I don't need to worry about booting up the system, getting it on the network, etc etc. This probably removes another order of magnitude of complexity from propellor as compared with d-i.

• Teaching propellor how to build a bootable image, containing a live Debian system and propellor. (Yes, this would mean reimplementing debian-live, but I estimate 100 lines of code to do it in propellor; most of the Properties needed already exist.) That image would then be booted up and perform the installation.
• Some kind of UI that generates the propellor config file.
• Adding Properties to partition the disk.

• Tandem skydive! or alternatively: a real "one-way" plane ticket
• Start point: ~4'250 meters above the ocean (14'000ft)
• End point: on the beach
• Total time: less than ten minutes
• Time in "real" free fall: according to Wikipedia, around 12 seconds, with most of the terminal velocity being reached at about 8 seconds
• Terminal velocity: ~190Km/h, ~120mph (again, according to Wikipedia)
• Time in "fake" free fall until the chute opened: around one minute
• Time spent going slowly down, with a few fun manoeuvres: don't remember, 3-5 minutes?

(If I've linked you to this page, it is my feeble attempt to provide a more convincing justification.)

• DLA 88-1 for ruby1.8 fixing several CVEs as described in the announcement.
• DLA 91-1 for tomcat6, mostly prepared by one of it's maintainers, Tony Mancill, also fixing several issues by upgrading to a new upstream version. I just did review, testing, release and announcement, and then figured out the proper versioing for Wheezy, which turned out to be problematic because using the recommend versioning breaks the upgrade paths, when new upstream versions are introdued to squeeze-lts which basically have same version as in will be (or are) in wheezy-security. One cause (besides the wrong recommendation which still needs fixing in our wiki page are non enforcable version constraints: the suites wheezy and squeeze-lts reside on ftp-master.debian.org (and wheezy is only updated on point releases), while wheezy-security resides on security.debian.org. Most probably we will still leave things as they are for squeeze-lts and do changes for wheezy-lts only. Oh, and the release of the tomcat6 update for wheezy is currently stalled by #770769.
• DLA 92-1 for tomcat-native was also done in cooperation with Tony and is also a new upstream release, which is needed as the old version of tomcat-native doesn't function with the new tomcat6 version.
• The 2.6.32.64 update of linux-2.6 has not happened yet, but is planned for the coming weekend. So far it has been done in collaboration of Moritz M hlenhoff from the security team, Ben Hutchings from the kernel team, and Rapha l Hertzog and myself from the LTS team, which I consider to be quite nice. As Rapha l had already explained, Ben has joined the LTS team and so far his contribution was to identify a problem in patch related to openvz, so I haven't published this kernel update yet. Also, there was zero feedback from testers for the openvz flavor packages - so if you are using openvz and squeeze kernels, please contact us. For all the other flavors there was positive feedback to the call for testing (thanks!) - so you might want to give these kernels a try too!

Psychologists use the term automatic negative thoughts to describe the ideas that pop into our heads uninvited, like burglars, and leave behind a mess of uncomfortable emotions. In the 1960s, one of the founders of cognitive therapy, Aaron Beck, concluded that ANTs sabotage our best self, and lead to a vicious circle of misery: creating a general mindset that is variously unhappy or anxious or angry (take your pick) and which is (therefore) all the more likely to generate new ANTs. We get stuck in the same old neural pathways, having the same negative thoughts again and again.

I tell people that my camera is a healing mechanism, Allah says. Let me photograph it and take it away from you.

There was a time when it was essentially illegal to be gay. There was a time when it was legal to own people and illegal for them to run away. Sometimes, society gets it wrong. And it s not just nameless bureaucrats; it s men like Thomas Jefferson. When that happens, strong privacy protections including collection controls that let people pick who gets their data, and when allow the persecuted and unpopular to survive.

• Ensure the binaries and data are installed into the right places in the directory hierarchy. Binaries must go to $prefix/bin, for example.
• Ensure that configuration can be found under /etc as well as under $prefix/etc

cd /path/to/my/project
lipkgen make-template

Format-Version: 1.0

Requires: Qt5Core (>= 5.3), Qt5DBus (>= 5.3), libpng12

lipkgen build pkginstall/

sudo lipa install package.ipk

runapp $ component_id -$ version :/bin/binary-name

int
foo()
 
        int *p, *q;
        p = q = 0;
        p = p;
        if (p == p)
                return 1;
        if ((p == q))
                return 2;
        return 0;
 

1. Use CCACHE_CPP2, as discussed in part 2. With ccache 3.2, you can now also put this into a configuration file: run_second_cpp = true in ~/.ccache/ccache.conf
2. Turn off the warnings mentioned above: -Wno-parentheses-equality, -Wno-tautological-compare, -Wno-self-assign (and any others you might find). One might think that these are actually useful warnings that one might want to keep, but GCC doesn t warn about them, and if you develop primarily with GCC, your code might contain these issues anyway. In particular, I have found that -Wno-tautological-compare is necessary for legitimate code.

• clang-3.5
  • Using ccache is 10% slower than not using it at all.
  • Using ccache with CCACHE_CPP2 on is another 10% slower.
• gcc-4.8
  • Using ccache is 19% slower than not using it at all.
  • Using ccache with CCACHE_CPP2 is another 9% slower.

run_second_cpp = true

• #752465 libgdbm3: "Multi-Arch:same file conflict for any pair of architectures"
  propose to close as duplicate, done so by release team
• #759960 src:libcatalyst-engine-psgi-perl: "libcatalyst-engine-psgi-perl: FTBFS: dh_auto_test: make -j1 test returned exit code 2"
  request package removal (pkg-perl)
• #767010 kadu-dev: "kadu-dev: KaduTargets.cmake hardcodes amd64 path"
  raise severity, ask about potential fix in recent upload, then close
• #767671 ekeyd: "ekeyd: fails to remove: subprocess installed post-removal script returned error exit status 1"
  apply patch from Cameron Norman, upload to DELAYED/2
• #767842 ruby-actionpack-action-caching: "ruby-actionpack-action-caching: fails to upgrade from 'wheezy' - trying to overwrite /usr/lib/ruby/vendor_ruby/action_controller/caching/actions.rb"
  propose patch (adding Breaks+Replaces), closed by maintainer the same way
• #768710 src:biojava3-live: "biojava3-live: FTBFS in jessie: dh_install: libbiojava3-java-doc missing files (doc/biojava/*), aborting"
  propose patch (add encoding information)
• #768798 libgdbm3: "libgdbm3:i386: changelog.Debian.gz different from libgdbm3:amd64"
  diagnose as possible duplicate of #752465
• #769214 src:dmtcp: "dmtcp: FTBFS in jessie: test failures"
  add info to the bug report
• #769336 request-tracker4: "request-tracker4: fails to upgrade from 'wheezy': /usr/share/dbconfig-common/scripts/request-tracker4/upgrade/sqlite3/4.2.3 exited with non-zero status [SEGFAULT]"
  add info to the bug report, tag unreproducible, close later
• #769670 ola-rdm-tests: "ola-rdm-tests: FTBFS in a sid chroot with pbuilder (no network)"
  provide more test results
• #769820 par2: "par2: "par2repair file.par2 *" buggy, fixed in latest git version 0.6.11"
  sponsor maintainer upload
• #769833 src:trac: "[trac] Some sources are not included in your package"
  propose patch which repacks the tarball, applied and uploaded by maintainer
• #770411 mpi-specs: "mpi-specs: postinst uses /usr/share/doc content (Policy 12.3)"
  drop (broken call from postinst and then whole) postinst, upload to DELAYED/5
• #770648 src:hiredis: "hiredis: FTBFS: Test failure"
  more triaging/testing
• #770762 src:libinline-java-perl: "libinline-java-perl: Build dependencies are too loose"
  upload package prepared by Peter Pentchev (pkg-perl)
• #770844 src:libinline-java-perl: "[libinline-java-perl] FTBFS twice in a row"
  upload package prepared by Peter Pentchev (pkg-perl)
• #770845 src:libinline-java-perl: "[libinline-java-perl] FTBFS: Assumes a decimal point during the tests"
  upload package prepared by Peter Pentchev (pkg-perl)
• #771361 sponsorship-requests: "RFS: roxterm/2.9.5-1"
  sponsor maintainer upload

It has to be as fast as possible, so interpreted languages are out. You don't want to micro manage memory, so C is out. You don't want to require programmers to have a degree, so C++ is out. You want fast startup and not depend on a big runtime, so Java is out. [...] (Bram Moolenaar)

Do not call up what you cannot put down.

/*
 * constexpr tells the compiler that a variable or function can be evaluated at
 * compile time.
 *
 * constexpr functions can also be run at run time, if they are called with
 * values not known at compile time.
 *
 * See http://en.cppreference.com/w/cpp/language/constexpr for more nice examples
 *
 * It can be used to avoid using constants in code, and using instead functions
 * for computing hardware bitfields or physical values, without losing in
 * efficiency.
 */
#include <iostream>
using namespace std;
constexpr int factorial(int n)
 
    return n <= 1 ? 1 : (n * factorial(n-1));
 
int main()
 
    cout << "Compile time factorial of 6: " << factorial(6) << endl;
    cout << "Enter a number: ";
    int a;
    cin >> a;
    cout << "Run time factorial of " << a << ": " << factorial(a) << endl;
 

        const char* code = R"--(
          printf("foo\tbar\n");
          return 0;
        )--";

#include <string>
#include <iostream>
#include <unordered_set>
using namespace std;
// std::initializer_list< >
//   will have as its value all the elements inside the curly braces
string join(initializer_list<string> strings)
 
    string res;
    for (auto str: strings)
     
        if (!res.empty())
            res += ", ";
        res += str;
     
    return res;
 
int main()
 
    unordered_set<string> blacklist  ".", "..", ".git", ".gitignore"  ;
    cout << join(  "antani", "blinda"  ) << endl;
 

        auto i = 3 + 2;
        // See also https://github.com/esseks/monicelli
        vector<string> names  "antani", "blinda", "supercazzola"  ;
        for (auto i = names.cbegin(); i != names.cend(); ++i)
            cout << i;
        template<typename T>
        T frobble(const T& stuff)
         
             // This will work whatever type is returned by stuff.read()
             auto i = stuff.read();
             //  
         

        for (auto i: list_of_stuff)
                cout << i << endl;
        for (auto n:  0,1,2,3,4,5 )
                cout << n << endl;
        // This construct:
        for (auto i: stuff)
        // If stuff is an array, it becomes:
        for (i = stuff, i < stuff + sizeof(stuff) / sizeof(stuff[0]); ++i)
        // If stuff has .begin() and .end() methods it becomes:
        for (i = stuff.begin(); i != stuff.end(); ++i)
        // Otherwise it becomes:
        for (i = begin(stuff); i != end(stuff); ++i)
        // And you can define begin() and end() functions for any type you
        // want, at any time

// JavaScript
var add = function(a, b)   return a + b;  

# Python
add = lambda a, b: a + b

auto add = [](int a, int b)   return a + b;  

// JavaScript
var a = 0;
$.each([1, 2, 3, 4], function(idx, el)   a += el  );

unsigned a = 0;
std::for_each(  1, 2, 3, 4  , [&a](int el)   return a += el;  );

        tuple<int, string, vector<string>> parse_stuff()
         
                return make_tuple(id, name, values);
         
        string name; vector<string> values;
        // std::ignore can be used to throw away a result
        tie(ignore, name, values) = parse_stuff();
        // std::tie can also be used to do other kind of
        // multi-operations besides assignment:
        return tie(a, b, c) < tie(a1, b1, c1);
        // Is the same as:
        if (a != a1) return a < a1;
        if (b != b1) return b < b1;
        return c < c1;

        std::regex re(R"((\w+)\s+(\w+))");
        string s("antani blinda");
        smatch res;
        if (regex_match(s, res, re))
            cout << "OK " << res[1] << " -- " << res[2] << endl;

    unique_ptr<dirent, std::function<void(void*)>> dirbuf((dirent*)malloc(len), free);

string errno_str(int error)
 
    char buf[256];
#if (_POSIX_C_SOURCE >= 200112L   _XOPEN_SOURCE >= 600) && ! _GNU_SOURCE
    strerror_r(errno, buf, 256);
    string res(buf);
#else
    string res(strerror_r(errno, buf, 256));
#endif
    return res;
 
[ [noreturn]] void throw_libc_error(int error)
 
    throw runtime_error(errno_str(error));
 

db.query(R"(
   INSERT INTO table NAMES (id, name, description)
     VALUES (?, ?, ?)
)", 4, "genio", "fantasia, intuizione, decisione, e velocit  di esecuzione");

apt-get install postfix dovecot-imapd

Postfix The two interesting files to configure postfix are /etc/postfix/main.cf and /etc/postfix/master.cf. A commented version of the former exists in /usr/share/postfix/main.cf.dist. Alternatively, there is the ~600k word strong man page postconf(5). The latter file is documented in master(5).

/etc/postfix/main.cf I changed the following in my main.cf

@@ -37,3 +37,9 @@
 mailbox_size_limit = 0
 recipient_delimiter = +
 inet_interfaces = all
+
+home_mailbox = Mail/
+smtpd_recipient_restrictions = permit_mynetworks reject_unauth_destination permit_sasl_authenticated
+smtpd_sasl_type = dovecot
+smtpd_sasl_path = private/auth
+smtp_helo_name = my.reverse.dns.name.com

At this point, also make sure that the parameters smtpd_tls_cert_file and smtpd_tls_key_file point to the right certificate and private key file. So either change these values or replace the content of /etc/ssl/certs/ssl-cert-snakeoil.pem and /etc/ssl/private/ssl-cert-snakeoil.key. The home_mailbox parameter sets the default path for incoming mail. Since there is no leading slash, this puts mail into $HOME/Mail for each user. The trailing slash is important as it specifies qmail-style delivery'' which means maildir. The default of the smtpd_recipient_restrictions parameter is permit_mynetworks reject_unauth_destination so this just adds the permit_sasl_authenticated option. This is necessary to allow users to send email when they successfully verified their login through dovecot. The dovecot login verification is activated through the smtpd_sasl_type and smtpd_sasl_path parameters. I found it necessary to set the smtp_helo_name parameter to the reverse DNS of my server. This was necessary because many other email servers would only accept email from a server with a valid reverse DNS entry. My hosting provider charges USD 7.50 per month to change the default reverse DNS name, so the easy solution is, to instead just adjust the name announced in the SMTP helo.

/etc/postfix/master.cf The file master.cf is used to enable the submission service. The following diff just removes the comment character from the appropriate section.

@@ -13,12 +13,12 @@
 #smtpd     pass  -       -       -       -       -       smtpd
 #dnsblog   unix  -       -       -       -       0       dnsblog
 #tlsproxy  unix  -       -       -       -       0       tlsproxy
-#submission inet n       -       -       -       -       smtpd
-#  -o syslog_name=postfix/submission
-#  -o smtpd_tls_security_level=encrypt
-#  -o smtpd_sasl_auth_enable=yes
-#  -o smtpd_client_restrictions=permit_sasl_authenticated,reject
-#  -o milter_macro_daemon_name=ORIGINATING
+submission inet n       -       -       -       -       smtpd
+  -o syslog_name=postfix/submission
+  -o smtpd_tls_security_level=encrypt
+  -o smtpd_sasl_auth_enable=yes
+  -o smtpd_client_restrictions=permit_sasl_authenticated,reject
+  -o milter_macro_daemon_name=ORIGINATING
 #smtps     inet  n       -       -       -       -       smtpd
 #  -o syslog_name=postfix/smtps
 #  -o smtpd_tls_wrappermode=yes

Dovecot Since above configuration changes made postfix store email in a different location and format than the default, dovecot has to be informed about these changes as well. This is done in /etc/dovecot/conf.d/10-mail.conf. The second configuration change enables postfix to authenticate users through dovecot in /etc/dovecot/conf.d/10-master.conf. For SSL one should look into /etc/dovecot/conf.d/10-ssl.conf and either adapt the parameters ssl_cert and ssl_key or store the correct certificate and private key in /etc/dovecot/dovecot.pem and /etc/dovecot/private/dovecot.pem, respectively. The dovecot-core package (which dovecot-imapd depends on) ships tons of documentation. The file /usr/share/doc/dovecot-core/dovecot/documentation.txt.gz gives an overview of what resources are available. The path /usr/share/doc/dovecot-core/dovecot/wiki contains a snapshot of the dovecot wiki at http://wiki2.dovecot.org/. The example configurations seem to be the same files as in /etc/ which are already well commented.

/etc/dovecot/conf.d/10-mail.conf The following diff changes the default email location in /var/mail to a maildir in ~/Mail as configured for postfix above.

@@ -27,7 +27,7 @@
 #
 # <doc/wiki/MailLocation.txt>
 #
-mail_location = mbox:~/mail:INBOX=/var/mail/%u
+mail_location = maildir:~/Mail
 
 # If you need to set multiple mailbox locations or want to change default
 # namespace settings, you can do it by defining namespace sections.

/etc/dovecot/conf.d/10-master.conf And this enables the authentication socket for postfix:

@@ -93,9 +93,11 @@
    
 
   # Postfix smtp-auth
-  #unix_listener /var/spool/postfix/private/auth  
-  #  mode = 0666
-  # 
+  unix_listener /var/spool/postfix/private/auth  
+    mode = 0660
+    user = postfix
+    group = postfix
+   
 
   # Auth process is run as this user.
   #user = $default_internal_user

Aliases Now Email will automatically put into the '~/Mail' directory of the receiver. So a user has to be created for whom one wants to receive mail...

$ adduser josch

...and any aliases for it to be configured in /etc/aliases.

@@ -1,2 +1,4 @@
-# See man 5 aliases for format
-postmaster:    root
+root:       josch
+postmaster: josch
+hostmaster: josch
+webmaster:  josch

After editing /etc/aliases, the command

$ newaliases

has to be run. More can be read in the aliases(5) man page.

Finishing up Everything is done and now postfix and dovecot have to be informed about the changes. There are many ways to do that. Either restart the services, reboot or just do:

$ postfix reload
$ doveadm reload

Have fun!

• #762672 - qt-at-spi: when this package is installed, other programs fail to run
• #740998 - NetworkManager and rdnssd do not play well together
• #756253 - Upgrade from 2.02~beta2-10 to 2.02~beta2-11 left grub unbootable
• #762638 - missing source: Configure
• #718624 - transmission-daemon: segfaults with systemd due to erroneous maintainer scripts
• #727149 - linux-image-3.10-3-amd64: Network adapter (Intel 82579V) hangs during TX, causing reset and undetected data corruption at the other side
• #755202 - network-manager: keeps creating and using new connection "eth0" that does not work
• #706877 - insserv: breaks dist-upgrade by installing before packages fix their init scripts
• #741464 - grub-pc-bin: freezes after "terminal_input at_keyboard"
• #764798 - grub2: Grub rescue shell with RAID 6 mdadm over 8 disks

• In Total: 1143 (Including 186 bugs affecting key packages)
  • Affecting Jessie: 274 (key packages: 131) That's the number we need to get down to zero before the release. They can be split in two big categories:
    • Affecting Jessie and unstable: 189 (key packages: 99) Those need someone to find a fix, or to finish the work to upload a fix to unstable:
      • 46 bugs are tagged 'patch'. (key packages: 27) Please help by reviewing the patches, and (if you are a DD) by uploading them.
      • 11 bugs are marked as done, but still affect unstable. (key packages: 5) This can happen due to missing builds on some architectures, for example. Help investigate!
      • 132 bugs are neither tagged patch, nor marked done. (key packages: 67) Help make a first step towards resolution!
    • Affecting Jessie only: 85 (key packages: 32) Those are already fixed in unstable, but the fix still needs to migrate to Jessie. You can help by submitting unblock requests for fixed packages, by investigating why packages do not migrate, or by reviewing submitted unblock requests.
      • 59 bugs are in packages that are unblocked by the release team. (key packages: 18)
      • 26 bugs are in packages that are not unblocked. (key packages: 14)