Commands by ryanchapman (5)

  • Need to encrypt something from the command line? I've used this before to encrypt passwords with a master password that was shared amongst a team. To decrypt: ~$ echo -n 'jA0EAwMCPdknsznAww5gySL1/quqhXg6QgQkIz5abzGP5EZgTbXCFU+y6dP8ySWovytc' | base64 --decode | gpg --decrypt gpg: CAST5 encrypted data Enter passphrase: secret gpg: encrypted with 1 passphrase HelloWorld! Show Sample Output


    0
    echo 'HelloWorld!' | gpg --symmetric | base64
    ryanchapman · 2013-07-06 08:30:35 1
  • Copies a directory structure from /home/ to /backups/home (notice that the destination does not have a trailing slash)


    1
    BEGIN=`date`; rsync -avxW /home/ /backups/home ; echo "Begin time: $BEGIN" ; echo "End time..: `date`"
    ryanchapman · 2013-07-06 08:24:45 0
  • How to figure out what a program is doing. -tt detailed timestamps -f also strace any child processes -v be very verbose, even with common structures -o write output to file -s N capture up to N characters of strings, rather than abbreviating with ...


    0
    strace -ttvfo /tmp/logfile -s 1024 program
    ryanchapman · 2013-07-06 08:19:29 0
  • Shows a constantly updating display of disk IO activity. Two sections are in the output. The first is the IO activity since the machine was booted, the second section is the IO activity in the last second Show Sample Output


    0
    watch -n 1 'iostat -xmd 1 2'
    ryanchapman · 2013-07-06 08:07:32 0
  • If on a web server (with access to the ssl key), decrypt SSL off the wire


    0
    openssl pkcs8 -in /etc/pki/tls/web.key -out /root/wc.key -nocrypt && tshark -o "ssl.desegment_ssl_records:TRUE" -o "ssl.desegment_ssl_application_data:TRUE" -o "ssl.keys_list:,443,http,/root/wc.key" -o "ssl.debug_file:rsa.log" -R "(tcp.port eq 443)"
    ryanchapman · 2013-07-06 08:01:36 12

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cycle through a 256 colour palette
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Simple command to convert a large number of images into jpeg-format. Will delete originals after conversion.

Using column to format a directory listing
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Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

One liner to parse all epubs in a directory and use the calibre ebook-convert utility to convert them to mobi format
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Kill most recently created process.
Kills the most recently created firefox process.

ping with timestamp

sort ugly text
Often, when sorting you want the sort to ignore extraneous characters. The b, d, and f tell sort to ignore leading blanks, use 'dictionary order' (ignore punctuation), and ignore (fold) case. Add a "u" if you only want one copy of duplicate lines. This is a great command to use within vim to sort lines of text, using !}sort -bdf

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.


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