GNU/Linux basic VI commands

Text edit

a[text toevoegen na] i[text toevoegen voor] o[text onder toevoegen] O[text boven toevoegen] R[text overschrijven]

Text delete

d[getal+richting verwijderen] d$[verwijder text tot einde regel] dd[verwijder hele regel] x[verwijder huidig character] X[verwijder vorig character] J[koppel de huidige en de volgende regel aan elkaar]

Copy / Paste

y[getal+richting naar buffer kopieren] yw[woord naar buffer kopieren] p[plaats buffer na] P[plaats buffer voor]


u[ongedaan maken] ~[hoofdletters/kleine letters]

File management

:wq[bestand opslaan en afsluiten :w[bestand opslaan] :q[afsluiten] :q![geforceerd afsluiten zonder opslaan]


Categorized as GNU/Linux Tagged

LINUX Loop Device

You can create a loopback or iSCSI file using dd. The following example creates a file with an initial size o 0 bytes and a allocated size of 8Gb.

dd if=/dev/zero of=LUN3 bs=1000 count=0 seek=$[1000*1000*8]

Mount the file using the following command.

mount -o loop /path/to/file /path/to/mountpoint


OpenSSL Certificate Commands & Examples

Below script creates al selfgesigned certificate from a private key and removes the password from the key so you can you can use the key-pair in Apache.

# Create Key and Certificate Signing Request (option -des3 creates a triple des encrypted key)...
openssl genrsa -des3 -out server.key 4096
openssl req -new -key server.key -out server.csr

# Remove password from key and sign certificate with key... 
cp server.key
openssl rsa -in -out server.key
openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt

For ease you can add all key and signing options to a config file. This way you can also add a subjectAlternate to the certificate.

>openssl req -new -config server.cnf -key server.key -out server.csr

# server.cnf #
[ req ]
default_bits = 4096
prompt = no
encrypt_key = no
distinguished_name = dn
req_extensions = req_ext

[ dn ]
C = NL
O = Totietoot
CN =

[ req_ext ]
subjectAltName =,

Use the following command to convert the key-pair to pkcs12 format.

openssl pkcs12 -export -in server.crt -inkey server.key [-name tomcat] -out server.p12 -CAfile chain.pem -caname root -chain

Convert pkcs12 file to java keystore (jks):

keytool -importkeystore -deststorepass <password> -destkeypass <password> -destkeystore server.jks -srckeystore server.p12 -srcstoretype PKCS12 -srcstorepass <password> -alias <name>

Decode a certificate request or a x509 certificate:

openssl req -in server.csr -noout -text
openssl x509 -in server.crt -noout -text

Convert a PFX file to PEM-format (single file)…

openssl pkcs12 -in server.pfx -out key-n-certs.pem -nodes

Check certificate and connection using openssl…

openssl s_client -showcerts -connect f.q.d.n:1234

Convert certificate (PEM) to public key…

openssl x509 -inform pem -in certificate.cer -pubkey -noout > pubkey.pem

Add a (CA) certificate to the JAVA CACerts certificate truststore…

"C:\Java\jdk1.8.0_121\bin\keytool" -import -alias ADCERT-CA-1 -keystore "C:\Java\jdk1.8.0_121\jre\lib\security\cacerts" -trustcacerts -file ADCERT-CA-1.cer