Tag Archives: command line

cat: create/write file

Create file without replacing variables:

cat <<'EOF' > /path/file
============================
My name is ${0}
I was input via user data
============================
EOF

cat <<'EOF' > /path/file

============================

My name is ${0}

I was input via user data

============================

EOF

If you check /path/file you will see exactly the content above.
Create file REPLACING the variables while creating:

cat <<EOF > /path/file
============================
My name is ${0}
I was input via user data
============================
EOF

cat <<EOF > /path/file

============================

My name is ${0}

I was input via user data

============================

EOF

In this example, the variable ${0} will be replaced during the creation of the file, hence the content will display your username.

Verify that private key and SSL certificate are matching via command line

# openssl rsa -modulus -noout -in private_key.key | openssl md5
(stdin)= b650539so2020gwoge778b6981a38c

# openssl x509 -modulus -noout -in mysite_certificate.crt | openssl md5
(stdin)= b650539so2020gwoge778b6981a38c

# openssl rsa -modulus -noout -in private_key.key | openssl md5

(stdin)= b650539so2020gwoge778b6981a38c

# openssl x509 -modulus -noout -in mysite_certificate.crt | openssl md5

(stdin)= b650539so2020gwoge778b6981a38c

the outputs must match 🙂

Send attachment via command line in Linux

You can do that using mpack

mpack -s "This is the subject" -d body.txt attachment.zip myemail@mydomain.com

1	mpack -s "This is the subject" -d body.txt attachment.zip myemail@mydomain.com

GIT basic commands

Check branch

git branch <name new branch>

1	git branch <name new branch>

Show changes after your last commit

git diff

git diff

rollback to previous change (specific file) to the latest commit

git checkout -- testfile

1	git checkout -- testfile

Delete branch

git branch -D <branch name>

1	git branch -D <branch name>

Push new branch to the origin (my ‘git space’)

git push -u origin <branch name>

1	git push -u origin <branch name>

Restore file from upstream

git checkout upstream/master -- <filename>

1	git checkout upstream/master -- <filename>

Commit changes in one single line

git commit -a -m "comment"

1	git commit -a -m "comment"

If you want to merge the recent changes committed on the master branch into your dev branch

git checkout dev      # gets you "on branch dev"
git fetch origin        # gets you up to date with origin
git merge origin/master

git checkout dev # gets you "on branch dev"

git fetch origin # gets you up to date with origin

git merge origin/master

If you want to reset ALL from the version ‘on the web’

git fetch origin
git reset --hard origin/<branch>

1 2	git fetch origin git reset --hard origin/<branch>

Source: http://rogerdudler.github.io/git-guide/

Docker basic commands

Check containers

# docker ps -a

1	# docker ps -a

Connect to a container

# docker start <ID>
# docker attach <ID>

1 2	# docker start <ID> # docker attach <ID>

Exit from a container

-> type 'exit'

1	-> type 'exit'

Remove all of Docker containers:

docker stop $(docker ps -a -q)
docker rm $(docker ps -a -q)

1 2	docker stop $(docker ps -a -q) docker rm $(docker ps -a -q)

SSL – Check if a certificate matches with its public key

# openssl rsa -modulus -noout -in private_key.key | openssl md5
(stdin)= jhg557dd83jdlki93de778b69ojg536

# openssl x509 -modulus -noout -in certificate.crt | openssl md5
(stdin)= jhg557dd83jdlki93de778b69ojg536

# openssl rsa -modulus -noout -in private_key.key | openssl md5

(stdin)= jhg557dd83jdlki93de778b69ojg536

# openssl x509 -modulus -noout -in certificate.crt | openssl md5

(stdin)= jhg557dd83jdlki93de778b69ojg536

Mac tricks – command line

Strange wake up of your Mac
To disable Bonjour (mDNSResponder – NoMulticastAdvertisements ):

sudo defaults write /System/Library/LaunchDaemons/com.apple.mDNSResponder ProgramArguments -array-add "-NoMulticastAdvertisements"

1	sudo defaults write /System/Library/LaunchDaemons/com.apple.mDNSResponder ProgramArguments -array-add "-NoMulticastAdvertisements"

To re-enable Bonjour:

sudo defaults write /System/Library/LaunchDaemons/com.apple.mDNSResponder ProgramArguments -array "/usr/sbin/mDNSResponder" "-launchd"

1	sudo defaults write /System/Library/LaunchDaemons/com.apple.mDNSResponder ProgramArguments -array "/usr/sbin/mDNSResponder" "-launchd"

Disable Creation of Metadata Files on Network Volumes

defaults write com.apple.desktopservices DSDontWriteNetworkStores -bool true

1	defaults write com.apple.desktopservices DSDontWriteNetworkStores -bool true

Re-enable:

defaults write com.apple.desktopservices DSDontWriteUSBStores -bool true

1 2	defaults write com.apple.desktopservices DSDontWriteUSBStores -bool true

Save to Disk by Default and not on Cloud products

defaults write NSGlobalDomain NSDocumentSaveNewDocumentsToCloud -bool false

1	defaults write NSGlobalDomain NSDocumentSaveNewDocumentsToCloud -bool false

Power off memory during standy
hibernatemode supports values of 0, 3, or 25. Whether or not a hiberna-
tion image gets written is also dependent on the values of standby and
autopoweroff

For example, on desktops that support standby a hibernation image will be
written after the specified standbydelay time. To disable hibernation
images completely, ensure hibernatemode standby and autopoweroff are all
set to 0.

hibernatemode = 0 by default on desktops. The system will not back memory
up to persistent storage. The system must wake from the contents of mem-
ory; the system will lose context on power loss. This is, historically,
plain old sleep.

hibernatemode = 3 by default on portables. The system will store a copy
of memory to persistent storage (the disk), and will power memory during
sleep. The system will wake from memory, unless a power loss forces it to
restore from hibernate image.

hibernatemode = 25 is only settable via pmset. The system will store a
copy of memory to persistent storage (the disk), and will remove power to
memory. The system will restore from disk image. If you want “hiberna-
tion” – slower sleeps, slower wakes, and better battery life, you should
use this setting.

It is suggested to power off memory at stand-by with the following command:

sudo pmset hibernatemode 25

1	sudo pmset hibernatemode 25

Source: http://docs.hardentheworld.org/OS/OSX_10.11_El_Capitan/

Time Machine – Change Schedule

To change Time Machine schedule to run every day, run the following from your Terminal:

defaults write /System/Library/LaunchDaemons/com.apple.backupd-auto StartInterval -int 86400

1	defaults write /System/Library/LaunchDaemons/com.apple.backupd-auto StartInterval -int 86400

Source: http://www.markwheadon.com/blog/2009/03/changing-time-machine-backup-schedule/

Banana Pi Pro – WLAN configuration

Add ‘ap6210‘ to /etc/modules to enable WiFi, and use modprobe ap6210 to force load the module.

Check dmesg to see if all has been loaded correctly. If not, reboot and check again.

dmesg|grep WLAN

1	dmesg\|grep WLAN

Install the required packages:

apt-get install wireless-tools iw wpasupplicant

1	apt-get install wireless-tools iw wpasupplicant

Modify /etc/network/interfaces

# Dinamic IP:
auto wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp
wpa-ap-scan 1
wpa-scan-ssid 1
wpa-ssid "WIFI_NETWORK_NAME"
wpa-psk "WLAN-KEY"

# Static IP:
auto wlan0
allow-hotplug wlan0
iface wlan0 inet static
address 192.168.xx.yy
netmask 255.255.255.0
gateway 192.168.0.1
wpa-ap-scan 1
wpa-scan-ssid 1
wpa-ssid "WIFI_NETWORK_NAME"
wpa-psk "WLAN-KEY"

# Dinamic IP:

auto wlan0

allow-hotplug wlan0

iface wlan0 inet dhcp

wpa-ap-scan 1

wpa-scan-ssid 1

wpa-ssid "WIFI_NETWORK_NAME"

wpa-psk "WLAN-KEY"

# Static IP:

auto wlan0

allow-hotplug wlan0

iface wlan0 inet static

address 192.168.xx.yy

netmask 255.255.255.0

gateway 192.168.0.1

wpa-ap-scan 1

wpa-scan-ssid 1

wpa-ssid "WIFI_NETWORK_NAME"

wpa-psk "WLAN-KEY"

Bring the interface up:

ifconfig wlan0 up

1 2	ifconfig wlan0 up

Source: http://oyox.de/882-wlan-auf-bananian-banana-pi-einrichten/

Creating ISO images from a folder in OSX

hdiutil makehybrid -o /path/to/image.iso ~/path/to/folder/to/be/converted -iso -joliet

1	hdiutil makehybrid -o /path/to/image.iso ~/path/to/folder/to/be/converted -iso -joliet

This can be very handy if you need to add an ISO in a VM, mounting it via virtual CD ROM.

My notepad

Chris' IT notes…

Tag Archives: command line

cat: create/write file

Verify that private key and SSL certificate are matching via command line

Send attachment via command line in Linux

GIT basic commands

Docker basic commands

SSL – Check if a certificate matches with its public key

Mac tricks – command line

Time Machine – Change Schedule

Banana Pi Pro – WLAN configuration

Creating ISO images from a folder in OSX