GNU/Linux

All posts containing GNU/Linux-related scripts and patterns.

GNU/Linux ODATA Query Examples

/ GNU/Linux /
ODATA Query OptionDescription
$orderbyUri parameter for sorting…
$selectUri parameter to select specific coluimns…
$topUri parameter to limit the result…
$skipUri parameter to skip number of rows…
$filterUri parameter to filter result…
$expandUri parameter to expand related entity…
$inlinecountUri parameter to include a total record count…

Example to retrieve metadata from JBoss DV Odata service…

https://localhost:8443/odata/vdbname/$metadata

Retrieve all records in JSON format…

https://localhost:8443/odata/vdbname/modelname?$format=json

Order by column ‘Name’ and retrieve first 5 records…

https://localhost:8443/odata/vdbname/modelname?amp;$orderby=Name&$top=5

Order by column ‘Name’ and retrieve records 6-10 records…

https://localhost:8443/odata/vdbname/modelname?$orderby=Name&skip=5&$top=5

Filter ODATA result ($filter=Name eq ‘John’)…

https://localhost:8443/odata/vdbname/modelname?$filter=Name%20eq%20%27John%27

Select specific rows…

https://localhost:8443/odata/vdbname/modelname?$select=ID,Name,Description

GNU/Linux Test LDAP server SSL/TLS connection

/ GNU/Linux /

Test LDAP server SSL/TLS connection using LDAP commandline client…

ldapsearch -H ldaps://dc01.totietoot.nl -b "OU=Employees,OU=Totietoot,DC=Totietoot,DC=nl" "userPrincipalName=john@totietoot.nl" -W -D john@totietoot.nl -d 1
env LDAPTLS_REQCERT=never|allow|try|demand LDAPTLS_CACERT=/path/to/ca-cert.pem ldapsearch -H ldaps://dc01.totietoot.nl -b "OU=Employees,OU=Totietoot,DC=Totietoot,DC=nl" "userPrincipalName=john@totietoot.nl" -W -D john@totietoot.nl -d 1

GNU/Linux JBoss Fuse Shell ActiveMQ Commands

/ GNU/Linux /

Display basic queue information…

activemq:query -QQueue=* --view Name,EnqueueCount,DequeueCount,QueueSize

Display queue messages…

activemq:browse --amqurl tcp://localhost:61616  --user [username] --password [password] queue:[queuename]

Purge a specific message from the command line…

activemq:purge --msgsel "JMSMessageID='ID:XXXXXXXX-000000-0000000000000-0:0:00:0:0'" [queuename]

Purge all messages from a specific queue…

activemq:purge [queuename]

GNU/Linux OpenSSH QuickRef

/ GNU/Linux /

LocalForward/Dynamic tunnels & SFTP jumphost connection examples (commandline):

>ssh -L 1522:remote.hostname:1522 user@tunnel.hostname
>ssh -D 8080 user@tunnel.hostname
>sftp -o ProxyJump=user@jump.hostname:22 [-b ./batch.scr] user@dest.host.internal

LocalForward/Dynamic tunnels & SFTP jumphost connection examples (commandline and config):

>ssh dsthst

~/.ssh/config:
Host prxjmp
  Hostname jump.hostname
  Port 22
  User user
  LocalForward 7080 10.0.0.9:7080
  DynamicForward 8080
Host dsthst
  HostName dest.host.internal
  Port 22
  User user
  ProxyJump prxjmp
  IdentityFile ~/.ssh/other_key_location

Generate a SSH Key Pair:

>ssh-keygen -m PEM -t ecdsa -b 521
>ssh-keygen -m PEM -t ecdsa -b 521 -C "tim" -f /home/tim/tmp/id_ecdsa

Other algorithms:

>ssh-keygen -t ed25519
>ssh-keygen -t dsa 
>ssh-keygen -t rsa -b 4096

Convert SSH2 Public Key to OpenSSH Public Key

>ssh-keygen -i -f id_ssh2.pub [-m PKCS8]

Convert OpenSSH Public Key to SSH2 Public Key

>ssh-keygen -e -f id_openssh.pub

Get Key Fingerprint MD5

ssh-keyscan -p [port] [hostname] > [hostkeyfpfile]
ssh-keygen -l -f [hostkeyfpfile] -E md5

Start session with alternate key

sftp -o IdentityFile=/home/tim/.ssh/id_rsa_2 tim@server1

Implement group restrictions in /etc/ssh/sshd_config

# Group restrictions 
AllowGroups sshaccess

Match Group sshpubkeyonly
      PasswordAuthentication no

Match group sftpusers
    X11Forwarding no
    ChrootDirectory %h
    AllowTcpForwarding no
    ForceCommand internal-sftp

GNU/Linux GPG Basic Commands

/ GNU/Linux /

Some of my most used gpg commands…

# Generate a PGP key...
gpg --gen-key

# Sign a key...
gpg --default-key [KEYID-TO-SIGN-WITH] --sign-key [KEYID-TO-BE-SIGNED] 

# Revoke a key...
gpg --edit-key [KEYID]
>revkey

# List (secret) keys...
gpg --list(-secret)-keys

# Export a public key in ascii armor format...
gpg --armor --export [KEYID] > KeyName_Email_KEYID.pub.asc

# Export a private key in ascii armor format...
gpg --armor --export-secret-keys [KEYID] > KeyName_Email_KEYID.sec.asc

GIT Version Control Basics

/ GNU/Linux /

Clone a Repository, add files, commit and push to master

git clone [--recurse-submodules] ssh://git@gitlab.timvkn.nl:22/Project.git
git add [filename|-A]
git commit -a -m "Initial upload..."
git push -u origin master

Create a branch for the new release and check-out to the new branch

git branch release-4.1.11
git checkout release-4.1.11
git submodule update --init --recursive

Make the changes to the files and commit the changes

git commit -a -m "Change description..."

Mark as executable

git update-index --chmod=+x build.sh

Push to server

git push -u origin release-4.1.11

Merge changes with master branch

A) Merge with master takes place on server. Pull new master branch from server...
git checkout master
git pull -a

B) Merge all changes to the master locally and push to server...
git checkout master
git merge release-4.1.11
git push -u origin master

Delete old branch

git branch -d release-4.1.11
* Option -D deletes a not merged branch...

Display commits and force to specific commit

git reflog
git reset --hard e072e63

Add submodule

git submodule add https://github.com/dGlt/submodule Submodules

GNU/Linux RegExp basics

/ GNU/Linux /

RegExp basic encoding…

? = 0..1
* = 0..n
NULL  = 1..1
+ = 1..n
| = XOR
{3} = 3
{2,8} = 2-8 chars/numbers
^ = Matches beginning
$ = Matches end

Example RegExp

X-[0-9]?[0-9]-((0[1-9])|([1-2][0-9])|(3[0-2]))-[A-Z]{3}[0-9]{3,6}

Matching and Not-matching...
X-88-32-ABC123 -- MATCH
X-7-06-XYZ12345 -- MATCH
X-88-33-ABC123 -- NOTMATCH (33 not within 01-32)
X-88-32-ABC12 -- NOTMATCH (12 not 3-6 numbers)