Commands by alf (5)

  • This may be listed already but this command is useful to untar a specific directory to a different server.


    0
    cat tarfile.tar.gz | ssh server.com " cd /tmp; tar xvzf - directory/i/want"
    alf · 2011-02-11 17:10:01 1
  • Some servers don't have ssh-copy-id, this works in those cases. It will ask for the destination server, this can be IP, hostname, or user@hostname if different from current user. Ssh keygen will let you know if a pubkey already exists on your system and you can opt to not overwrite it.


    -2
    echo 'Host or User@Host?:'; read newserver && ssh-keygen -N "" -t rsa -f ~/.ssh/id_rsa ; ssh $newserver cat <~/.ssh/id_rsa.pub ">>" ~/.ssh/authorized_keys ; ssh $newserver
    alf · 2010-05-07 06:24:53 1
  • Interfaces like lo can be omitted from the beginning, there are probably better ways of doing this, i'm a noob at awk. Show Sample Output


    5
    ifconfig -a| awk '/^wlan|^eth|^lo/ {;a=$1;FS=":"; nextline=NR+1; next}{ if (NR==nextline) { split($2,b," ")}{ if ($2 ~ /[0-9]\./) {print a,b[1]}; FS=" "}}'
    alf · 2010-04-15 04:34:28 3
  • Will edit *.db files in the same directory with todays date. Useful for doing a mass update to domains on a nameserver, adding spf records, etc. Looks for a string starting with 200 or 201 followed by 7 numbers, and replaces with todays date. This won't overwrite Ip's but i would still do some double checking after running this. Make sure your server's date is correct, otherwise insert your own serial number. rndc reload should usually follow this command.


    7
    sed -i 's/20[0-1][0-9]\{7\}/'`date +%Y%m%d%I`'/g' *.db
    alf · 2010-03-24 07:28:58 3
  • Bash scrip to test if a server is up, you can use this before wget'ing a file to make sure a blank one isn't downloaded.


    -1
    if [ "$(ping -q -c1 google.com)" ];then wget -mnd -q http://www.google.com/intl/en_ALL/images/logo.gif ;fi
    alf · 2010-03-23 04:15:03 7

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Load file into RAM (cache) for faster accessing for repeated usage
Best result when file size less than half of RAM size

Show changed files, ignoring permission, date and whitespace changes
Only shows files with actual changes to text (excluding whitespace). Useful if you've messed up permissions or transferred in files from windows or something like that, so that you can get a list of changed files, and clean up the rest.

Find recursively, from current directory down, files and directories whose names contain single or multiple whitespaces and replace each such occurrence with a single underscore.
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One-liner to generate Self-Signed SSL Certificate+Key without any annoying prompts or CSRs
Handy if you want to quickly generate a self-signed certificate. Also can be used in your automated scripts for generating quick-use certificates.

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change directory to actual path instead of symlink path
If you use symlinks a lot, especially nested symlinks, this puts you back on the absolute path to command-line-fu-nirvana. (Note the backticks around pwd).


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