Various tips about things that I can never remember when using Linux, OpenBSD, Apache, LaTeX and a few other computery tools.

Split this page and use tags!

setxkbmap -layout us -variant intl -options "lv3:ralt_switch_multikey"

Dans /etc/hal/fdi/policy, par exemple 10-x11-input.fdi (templates are usually found in /usr/share/hal/fdi/policy/):

<?xml version="1.0" encoding="ISO-8859-1"?>
<deviceinfo version="0.2">
  <device>
    <!-- FIXME: Support tablets too. -->
    <match key="info.capabilities" contains="input.mouse">
      <merge key="input.x11_driver" type="string">mouse</merge>
      <match key="/org/freedesktop/Hal/devices/computer:system.kernel.name"
             string="Linux">
        <merge key="input.x11_driver" type="string">evdev</merge>
      </match>
    </match>

    <match key="info.capabilities" contains="input.keys">
      <!-- If we're using Linux, we use evdev by default (falling back to
           keyboard otherwise). -->
      <merge key="input.x11_driver" type="string">keyboard</merge>
      <match key="/org/freedesktop/Hal/devices/computer:system.kernel.name"
             string="Linux">
        <merge key="input.x11_driver" type="string">evdev</merge>
      </match>
      <match key="info.product" string="Dell Dell USB Keyboard">
        <merge key="input.x11_options.XkbModel" type="string">dellusbmm</merge>
      </match>
      <merge key="input.x11_options.XkbOptions" type="string">lv3:ralt_switch_multikey</merge>
      <merge key="input.x11_options.XkbVariant" type="string">intl</merge>
    </match>
  </device>
</deviceinfo>

Dans /etc/hal/fdi/policy/11-x11-input-synaptics.fdi:

<?xml version="1.0" encoding="ISO-8859-1"?>
<deviceinfo version="0.2">
  <device>
    <match key="info.capabilities" contains="input.touchpad">
      <match key="info.product" contains="Synaptics TouchPad">
	<merge key="input.x11_driver" type="string">synaptics</merge>
	<!-- Arbitrary options can be passed to the driver using 
	the input.x11_options property since xorg-server-1.5. -->
	<!-- EXAMPLE:
	<merge key="input.x11_options.LeftEdge" type="string">120</merge>
	-->
      </match>
      <match key="info.product" contains="AlpsPS/2 ALPS">
	<merge key="input.x11_driver" type="string">synaptics</merge>
      </match>
      <match key="info.product" contains="appletouch">
	<merge key="input.x11_driver" type="string">synaptics</merge>
      </match>
      <match key="info.product" contains="bcm5974">
	<merge key="input.x11_driver" type="string">synaptics</merge>
      </match>
    </match>
    <match key="input.x11_driver" string="synaptics">
      <merge key="input.x11_options.SHMConfig" type="string">true</merge>
      <merge key="input.x11_options.VertEdgeScroll" type="string">true</merge>
      <merge key="input.x11_options.HorizEdgeScroll" type="string">true</merge>
      <merge key="input.x11_options.CornerCoasting" type="string">true</merge>
      <merge key="input.x11_options.TapButton1" type="string">1</merge>
      <merge key="input.x11_options.TapButton2" type="string">2</merge>

      <merge key="input.x11_options.RightEdge" type="string">900</merge>
      <merge key="input.x11_options.BottomEdge" type="string">700</merge>
      <merge key="input.x11_options.EmulateTwoFingerMinZ" type="string">90</merge>
      <merge key="input.x11_options.VertTwoFingerScroll" type="string">true</merge>
      <merge key="input.x11_options.HorizTwoFingerScroll" type="string">true</merge>
    </match>
  </device>
</deviceinfo>

In the .htaccess file:

AuthUserFile /PATH/TO/.htpasswd
AuthName "Nice name"
AuthType Basic
<Limit GET>
    require valid-user
</Limit>

Create and maintain the .htpasswd file:

$ htpasswd -c /PATH/TO/.htpasswd user1
New password: 
Re-type new password: 
Adding password for user user1
$ htpasswd /PATH/TO/.htpasswd user2
New password: 
Re-type new password: 
Adding password for user user2

La clé:

$ openssl genrsa -out server.key 1024

La requète de certificat:

$ openssl req -new -key server.key -out server.csr

Le certificat:

$ openssl x509 -req -days 1000 -in server.csr -signkey server.key -out server.crt

Convertir un certificat binaire en pem:

$ openssl x509 -inform der -in certificate.crt -out certificate.pem

Référence: How to generate self-signed SSL certificates

Changer la passphrase d'une clé:

$ openssl rsa -in server.key -out server-newpass.key -passout "pass:PASS"

Voir le contenu d'un(e) demande de certificat/certificat/clé:

$ openssl req|x509|rsa -in cert.crt -text

Plusieurs noms pour un seul certificat (vu ici). Dans openssl-custom.cnf (ou celui du système, mais c'est moins propre):

[req]
...
req_extensions = v3_req

...

[ v3_req ]
# Extensions to add to a certificate request
basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment

# Some CAs do not yet support subjectAltName in CSRs.
# Instead the additional names are form entries on web
# pages where one requests the certificate...
subjectAltName          = @alt_names

[alt_names]
DNS.1 = IPADDRESS
DNS.2 = SECONDNAME
DNS.3 = THIRDNAME
...

Puis on génère le certificat comme à l'habitude mais en spécifiant le fichier de configuration à utiliser en plus:

$ openssl req -config openssl-custom.cnf -new -key server.key -out server.csr

In `$JAVA_HOME/lib/swing.properties`:

# Swing properties
swing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel

If java complains with a

Unexpected error:
javax.net.ssl.SSLException: java.lang.RuntimeException: Unexpected error: java.security.InvalidAlgorithmParameterException: the trustAnchors parameter must be non-empty

odds are that the $JAVA_HOME/jre/lib/security/cacerts file is empty (i.e. it's only 32 Bytes in size).

To recreate it from, say, Mozilla's list of trusted certificates, the following (tested on ArchLinux) can be done:

for FILE in /usr/share/ca-certificates/mozilla/*.crt; do
  keytool -deststorepass changeit -import -trustcacerts -keystore $JAVA_HOME/jre/lib/security/cacerts -file $FILE -alias `basename ${FILE/.crt/}` -noprompt
done

Le .procmailrc:

:0
$HOME/mbox

Le .mutt(ng)rc:

set mbox="~/mbox"
set spoolfile="~/mbox"

Et bien mieux.

• mettre Xft.dpi: 100 dans ~/.Xresources
• mettre xrdb -load ~/.Xresources dans ~/.xsession (si nécessaire)
• redémarrer X

Peut aussi marcher:

apt-get install xfonts-base-transcoded

nfs:/data/Sources on /data/Sources type nfs (rw,rsize=32768,wsize=16384,timeo=3,retrans=5,acregmin=1,acregmax=30,acdirmin=10,acdirmax=60,retry=1000,namlen=255,port=2049,mountprog=100005,nfsprog=100003,posix,bg,hard,intr,noac,udp,addr=192.168.1.64)

lambda-d5.mtek.chalmers.se:/lfs/d5.dd/mehani on /chalmers/users/mehani type nfs (rw,nosuid,hard,intr,grpid,proto=tcp,addr=129.16.61.41)

mount -oloop,offset=sector_size*partition_start -t vfat /opt/qemu/tempImage /mnt/tempImage

En général sector_size=512 et partition_start=63.

Pour être sûr:

fdisk -lu /opt/qemu/tempImage

pstoedit -f plot-svg fichier.eps fichier.svg´

Les noms des images sont du type img00.jpg à 50 Hz :

$ ffmpeg -f image2 -i img%02d.jpg -r 50 -vcodec mpeg4 vid.avi

Two-sided printing option for landscape documents:

lpr -o sides=two-sided-short-edge

Two-sided printing with proper folding depending on the printing orientation (i.e. tumble when landscape printing), in /etc/a2ps/a2ps-site.cfg:

Printer: atp-b15-nl2-p1 | #{lp} #o #?l|-oDuplex=DuplexTumble||

or (simpler)

Options: -s2

And stapling:

Variable: lp.options | #{lp} #o #?l|"-oStaple=1Staple(Left)"|"-oStaple=1Staple(Right)"|

Prevent psnup (and other psutils) from cancelling two-sided printing, as per this post.

Still in /etc/a2ps/a2ps-site.cfg:

Variable: forceduplex \
        cat /etc/a2ps/duplex.ps - 
Variable: forcetumble \
        cat /etc/a2ps/tumble.ps - 
Variable: lp.hook \
        #?d! #?l|#{forcetumble}|#{forceduplex}| | !!

With PS headers duplex.ps and tumble.ps setting the right options.

This can be done using pdftk.

$ pdftk form.pdf fill_form data.fdf output data.pdf

Unfortunately, the project seems to be dead…

PPPd and PPTPClient are needed for this to work

Using the PPTPClient-provided options, one can quickly create a new peer in, say, /etc/ppp/peers/pptppeer:

file /etc/ppp/options.pptp
name LOGIN
pty "/usr/sbin/pptp PPTPSERVER --nolaunchpppd"

#debug
#nodetach

Of course, the password needs to be added to the /etc/ppp/chap-secrets file:

# client        server  secret                  IP addresses
LOGIN           *       PASSWORD                *

Once a network connection has been established, the routes may have to be taken care of before and/or after the establishment of the :

$ sudo route add PPTPSERVER DEFAULTGW
$ sudo pppd call pptppeer
$ sudo route add default gw PPTPPEERGW

Where DEFAULTGW is the default route _before_ the PPTP link has been established, and PPTPPEERGW is the remote endpoint of the P-t-P connection.

First emerge the necessary package

$ sudo emerge pptpclient pppd

Then configure the new interface, with dependencies and needed route setup in /etc/conf.d/net:

config_ppp0=( "ppp" )
link_ppp0="pty 'pptp PPTPSERVER --nolaunchpppd'"
username_ppp0='LOGIN'
password_ppp0='PASSWORD'
pppd_ppp0=(
       "noauth"
       "defaultroute"
       "holdoff 3"
       "child-timeout 60"
       "lcp-echo-interval 15"
       "lcp-echo-failure 3"
       noaccomp noccp nobsdcomp nodeflate nopcomp novj novjccomp persist
)
depend_ppp0() {
       depend net
}

preup() {
	case $1 in
		ppp0)
			route add PPTPSERVER gw DEFAULTGW
			return 0
		;;
		*)
		;;
	esac
}

postup() {
	case $1 in
		ppp0)
			route add default gw PPTPPEERGW dev $1
			return 0
		;;
		*)
		;;
	esac
}

predown() {
	case $1 in
		ppp0)
			route del default gw PPTPPEERGW
			return 0
		;;
		*)
		;;
	esac
}

postdown() {
	case $1 in
		ppp0)
			route del PPTPSERVER gw DEFAULTGW
			return 0
		;;
		*)
		;;
	esac
}

Finally, the startup link has to be created, and can be used directly:

$ sudo ln -s /etc/init.d/net.lo /etc/init.d/net.ppp0
$ sudo /etc/init.d/net.ppp0 start