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convert

Dos2unix

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In Windows a new line, is a CR (carriage return) followed by LF (line feed). In Linux, it’s just LF. If you bring over a text file from Windows to Linux, sometimes you’ll end up with a file with a bunch of ^M at the end of each line, which will breaks a lot of things. To fix, just run dos2unix. 

dos2unix file.txt

PFX to PEM

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Here’s how to convert SSL certificate from PFX to PEM format. 

#!/bin/bash
 
echo "This script converts SSL certificates from PFX to PEM."
read -p 'Enter PFX Certificate Name  : ' cert_pfx
read -p 'Enter the Import Passphrase : ' import_passphrase
 
openssl pkcs12 -in $cert_pfx -nocerts -out cert-key.pem -passin pass:$import_passphrase -passout pass:$import_passphrase
openssl pkcs12 -in $cert_pfx -clcerts -nokeys -out cert-body.pem -passin pass:$import_passphrase -passout pass:$import_passphrase
openssl pkcs12 -in $cert_pfx -nodes -nokeys -out cert-chain.pem -passin pass:$import_passphrase -passout pass:$import_passphrase
sleep 3
openssl rsa -in key.pem -out cert-private.key -passin pass:$import_passphrase -passout pass:$import_passphrase

This was covered in an earlier post, but this script prompts you for the passphrase.

Here’s the expected output.

  • cert-key.pem
  • cert-body.pem
  • cert-chain.pem
  • cert-private.key

Bash Convert Bytes

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Here’s a function to convert bytes into kilo, mega, giga, tera up to zeta bytes.

function convert_bytes {
    bytes=$credits
    b=${bytes:-0}; d=''; s=0; S=(Bytes {K,M,G,T,E,P,Y,Z}B)
    while ((b > 1024)); do
        d="$(printf ".%02d" $((b % 1000 * 100 / 1000)))"
        b=$((b / 1000))
        let s++
    done
    echo "$b$d ${S[$s]}"
}
credits=2308974418330
echo $credits 
convert_bytes $credits

Result is:

2308974418330
2.30 TB

FFMPEG Convert TS to MP4

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If you have video files that are formatted in MPEG-2, video files with a .m2ts extension, you can convert them to MP4 using ffmpeg.

ffmpeg -i input.ts -c:v libx264 -c:a aac output.mp4

The video is encoded using open format H.264, while audio is encoded using AAC.

Convert File to UTF-8

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Here’s how to convert multiple files to UTF-8 format.

for file in *.csv; do
    iconv -f ascii -t utf-8 "$file" -o "${file%.txt}.utf8.csv"
done

Convert PFX to PEM format

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SSL certificates comes in multiple formats. Some providers will hand you over certificates in PFX format which comes in a single file. If you need to import it to AWS Certificate Manager, you will need to convert it from PFX to PEM format. The following set of commands uses OpenSSL and pkcs12 to convert a SSL certificate from PFX to PEM format.

openssl pkcs12 -in cert.pfx -nocerts -out key.pem
openssl rsa -in key.pem -out server.key
openssl pkcs12 -in cert.pfx -clcerts -nokeys -out cert.pem
openssl pkcs12 -in cert.pfx -nodes -nokeys -out chain.pem

It result in 3 files.

  • server.key is the private key
  • cert.pem is the certificate
  • cert.pem and chain.pem are the full chain.

Once you have them, you can the proceed to import it to ACM.

SSL Certificate Import

Multisite to Single Site

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I have a couple of WordPress blogs that are running multisite. I decided I don’t need the other blogs. So, I converted both sites to the standard or single WordPress site. The good news is that there’s no need to reinstall WordPress. It requires just a simple edit of a couple of WordPress files. The conversion was not as bad as I initially thought. Just follow the steps below.

5 Easy Steps

  1. Back up your database — just in case.
  2. Delete the blogs you don’t want.
  3. Edit wp-config.php.
  4. Edit .htaccess.
  5. Clean up your database.

1. Backing up your database — just in case. You can use several tools for backing up your blogs. You can use PHPMyAdmin or a WordPress backup plugin. You can also use the WordPress Export feature to save the blog in XML format in case you want to restore it in the future.

2. Delete the blogs you don’t want – Go to All blogs in the WordPress Dashboard. If you have multiple blogs, it will be listed here. Delete the ones you don’t want.

3. Edit wp-config.php. Remove the Multisite entries in wp-config.php.

define( 'MULTISITE', true );
define( 'SUBDOMAIN_INSTALL', false );
$base = '/wordpress/';
define( 'DOMAIN_CURRENT_SITE', 'localhost' );
define( 'PATH_CURRENT_SITE', '/wordpress/' );
define( 'SITE_ID_CURRENT_SITE', 1 );
define( 'BLOG_ID_CURRENT_SITE', 1 );

4. Change your .htaccess to the standard WordPress configuration.

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

5. Finally, remove the database tables that are no longer needed.

wp_blogs
wp_blog_versions
wp_registration_log
wp_signups
wp_site
wp_sitemeta