Notes

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Collection of notes

generate-pdf-lorem-ipsum-test-files-command-line.md

# generate pdf with lorem ipsum text for testing
#
lorem-ipsum --units paragraphs --count 100 > 100.txt
enscript 100.txt -o - | ps2pdf - 100.pdf

# values:
# 100: 18kb 8pg
# 1000: 161kb 76pg
# 10000: 1.6mb 761pg
# 100000: 16mb 7508pg
# 500000: 80mb 37526pg

oracle-linux-setup.md

add /etc/sudoers.d/vagrant
vagrant ALL=(ALL) NOPASSWD: ALL
Defaults:vagrant !requiretty
Defaults:vagrant visiblepw

/etc/sysconfig/network-scripts/ifcfg-eth0
remove HWADDR line (mac)
add ONBOOT=yes

/etc/udev/rules.d/70-persistent-net.rules
remove HWADDR attribute

yum update
yum install zip unzip telnet wget xz git scl-utils
yum clean all

gcc update
http://docs.oracle.com/cd/E37670_01/E59096/E59096.pdf
wget -O /etc/yum.repos.d/public-yum-ol6.repo http://public-yum.oracle.com/public-yum-ol6.repo
set enabled=1 for the software collection package in the repo file
yum install devtoolset-3-gcc devtoolset-3-gcc-c++

# parallels
yum install kernel-uek-devel
wget http://linux.dell.com/dkms/permalink/dkms-2.2.0.3-1.noarch.rpm
rpm -i dkms-2.2.0.3-1.noarch.rpm
enable ol6_UEKR3_latest repo in /etc/yum.repo.d/


add /etc/profile.d/node.sh
export PATH=/opt/node/bin:$PATH

su node
npm -g update
npm -g install forever nodemon nan node-gyp

# installing a node module requiring the 4.8+ gcc
scl enable devtoolset-3 bash
export CXX=gcc
npm install bignum

# java - lack of entropy in VM causes slow startup
edit /.../jre-version/lib/security/java.security
change securerandom.source to securerandom.source=/tmp/random.bin
generate file as dd if=/dev/urandom of=/tmp/random.bin bs=1MB count=10

regex-search-replace-vscode.txt

given a line like this

  email: something@somewhere.com

  change it to:

  email: 'something@somewhere.com'
  

(\w+)@(\w+)\.(\w+)
'$1@$2.$3'

tesseract-ocr-with-good-results.md

# OCR with good results
convert -density 160 -antialias -monochrome -background white -alpha off sample.pdf sample.png
tesseract sample.png out hocr
cat out.txt

text-to-pdf.md

enscript test.txt -o - | ps2pdf - test.pdf

translate-pdf-document-to-imaged-pdf-document.md

# extract pages as images
# rebundle to pdf
rm *.png; convert -density 160 -antialias -monochrome -background white -alpha off ../100.pdf out-%05d.png
rm *.pdf; convert *.png output.pdf