Commands by ryanchapman (5)

  • Encrypt/decrypt a string from the command line

    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
  • Backup a directory structure

    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
  • strace a program

    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
  • I/O activity on a machine

    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
  • Decrypt SSL

    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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Find the package that installed a command

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"

Determine command type (alias, keyword, function, builtin, or file)
Prints a string indicating whether a command is an alias, keyword, function, builtin, or file. I have used this in my BASH scripts to allow an external parameter to define which function to run, and ensure that it is a valid function that can indeed be run.

Convert file type to unix utf-8
converts encoding of a file to unix utf-8 useful for data files that contain what would be usable ascii text but are encoded as mpeg or some other encoding that prevents you from doing common manipulations like 'sed'

See system users

Convert text to lowercase
Usage: lower [STRING]...

Attach screen over ssh
Directly attach a remote screen session (saves a useless parent bash process)

list all executables in your path
If run in bash, this will display all executables that are in your current $PATH

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Merge various PDF files

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