How do I add my RSA or DSA keyfile in shell script itself for the connection so that I need to carry only one file on my USB pen drive instead of $HOME/.ssh/id_rsa file under Unix / Linux operating systems?
Linux / Unix / Apple OS X / BSD operating system stores your rsa / dsa private and public keys in your $HOME/.ssh/ directory. You can use the following syntax to specific a file from which the identity (private key) for RSA or DSA authentication is used by the ssh command:
ssh -i /path/to/your/rsa_or_dsa_file user@server1.cyberciti.biz |
The default is ~/.ssh/id_rsa and ~/.ssh/id_dsa for protocol version 2.
Shell Script Hack To Carry ~/.ssh/id_rsa And ~/.ssh/id_dsa In Script Itself
The shell script syntax is as follows:
#!/bin/bash /usr/bin/ssh -i $0 user@server1.cyberciti.biz exit ################################################## ### Append ~/.ssh/id_rsa or ~/.ssh/id_dsa here ### ################################################## -----BEGIN RSA PRIVATE KEY----- -----END RSA PRIVATE KEY----- |
Now just run a script and it will get connected to remote server called server1.cyberciti.biz:
$ ./path/to/your/script
Sample Shell Script
I use the following to rescue or connect to my home server called nas.cyberciti.biz:
WARNING! These examples may expose your private data as it contains the private key for authentication. These files (or shell script) contain sensitive data and should be readable by the user but not accessible by others (read/write/execute)#!/bin/bash _me="${0##*/}" _user="root" _port="22" _server="nas.cyberciti.biz" _args="[email protected]" ## Server name validation ## host $_server &>/dev/null [ $? -ne 0 ] && { echo "Server '$_server' not found. Set correct \$_server in $_me script."; exit 1; } ## Get in ## ssh -i "${_me}" -p $_port ${_user}@${_server} "$_args" exit ### Replace this with your actual key. This is not a valid key :P ### -----BEGIN RSA PRIVATE KEY----- MIIEpgIBAAKCAQEAxPzlOsgLM72jv93rj7Tcw5Sj6V797mLL7GoZKcQIFeo2e3G7 q69bTcaDwnaxf7vTCWdcJbgrQRGbZ6w1EzuB5xC0YYVF2TGlWu1L9n8rGvJQm0OH tyMMi+O5i+2VwED4gDaLuBE83IZpeaHn6PmSbV3JGstz4QkeW/PqT5XJyCS2qHzo lWkY/SGXXPn9rM+U5KOAwIdetMQooGdZGkaAWbqmm6Ujsqz6IeKOnP0sQNvvyvpv UQogLGnJDdI+hrhOtzVZ+qiHmUlJC8EgiWedRz3mFF9G3Z1LSUqR++NAGmGuZFph utrKNR9LRqis4FzqkGb9rpaT5749yZRqQgJdwwIDAQABAoIBAQCvFDaIsBOEwSAw /4TGDPHJwuqMGKmInrawQPxsapblI22Y+dTbGtgDoFSrGeNYrA89ZGg5/h4zjvqY gi4KEfG69NXddx5FlCJrVk0VoKEnKgcKeFK/Kp+UFapr+5YFcblr+w7jYi69sZk9 SfFc17SVD64V6o3rjLc28utmILNe9fHmyLyLuaOvrwrWu1qxds9npDEPHks+0PUN xaeFzI5zPqWQfiu7j3FjsG2h1QCGL/Uqd5+IYSCqouOgsWCD10PFlryKc9+3PXFU ZrvB2+U0/LmFcI3+MYgGsCiL3zQzOWZg6hV6mNCHXh5yq4SskKKsntpclF2nrWWx fUQ07ccBAoGBAPRd9nwUf8tobEGdRSKYM+JqL+DN7yUKqbZsrho9sfvxg537DZRo 24BFRD6GmnZWFq0pgTymDNIyGNI4NNj44VR+oqE4sfsQHRoJ2IJidgDvbZGJqo9Zu Uib40IdXvYe6rwgjfBaksVUkPNkUZuDGsWuFXvDsZ6ECOl4VHSm5dSPzAoGBAM5d iPnTwZwoXk2H/F1uwHiBm8ZB6x9FofiN06sf3Und1oQT74LwiHZL/1BA2Oh/kMls blwfHry3HCBXuFLudd4AV1y9XlonUA4OgcPm4KJJoWfOiRwyZgMNUf9oTl1neo/q p2pkwIauKUSXH1flZhgATQnKPZnIh6XEIlnNxeLxAoGBAIS/rrEFKc9EMNsMJox+ hmEPMmc7OBi1TDCvpXzX2yJ0tv1RbrUaqXNrLYGR+cMjTTpQe8aIphph4J4CrqLX wQD3sj1GvUZ7FVC1/0so9IqPyl60c8B/Od21+QItJebgAUm4jSZ33WXVQ8Dhlmmx RpyUXVkf88PBxBdr/OW3u+0FAoGBAKNB/iZerxGiIhDGHxGvl5b+OkVbSu5fgScI 1MWiaizQ0m+E8fut3Ndxghd0ZeVxXhLrtFcuy3tShW7U1t7NBfROYs7chXNfHIcy 235+ito1LgW0+rZm8nM+sAM7mSRETCo4SNiEq0Ug35GuvHfqVjtyQPwOKY26j4qq Xd6b2wyRAoGBAMt9sWTgSKUKHnSoxtRG5Yy+g3GainjT4Lc1JUJjBGr7bYio2ZB/ L/W4H2mtZpkx0kYSI+TdzTJh9W15Ck1z+NmZxmCb2rbr4ESjQpWd/9G4MLO6tLtP sAk1hN1HMU2hXR+ObvtODXamUQjBq72WXpqVgyhIF2TMMVWEMQAdf8Lg -----END RSA PRIVATE KEY----- |
Because of the potential for abuse, this file must have strict permissions: read/write for the user, and not accessible by others. Use the chown and chmod commands as follows:
chown vivek:vivek script
chmod 0700 script
Run the script as follows:
$ ./script
$ ./script uptime
Sample outputs:
07:46:03 up 13 days, 1:07, 1 user, load average: 0.00, 0.00, 0.00
See also:
- How to setup RSA and DSA based passwordless login.
- Sshpass: Use ssh password in a script.
- keychain: Set Up Secure Passwordless SSH Access For Backup Scripts
3 comment
Nice article and thanks for sharing it.
The shell script hack is tricky.
I strongly recommend encrypt your private key using:
This will ask you to set a passphrase for your key.
And incorporate the encrypted key into your shell script. It would look like this:
—–BEGIN RSA PRIVATE KEY—–
Proc-Type: 4,ENCRYPTED
DEK-Info: DES-EDE3-CBC,34B03A2FC16BDFAD
……………………………….
……………………………….
—–END RSA PRIVATE KEY—–
What does “${0##*/}” mean?