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Pressing Ctrl combined with 'a' will move the cursor to the beginning of the command under bash (other shells?). I used to do this after arrowing up for the last command, then typing 'sudo ' to run the last command as root, but of course the all time greatest command here `sudo !!` is more succinct. Still Ctrl+A can be very useful when you want to edit something at/close to the beginning of the command line.
Here is a command line to run on your server if you think your server is under attack. It prints our a list of open connections to your server and sorts them by amount.
BSD Version:
$ netstat -na |awk '{print $5}' |cut -d "." -f1,2,3,4 |sort |uniq -c |sort -nr
Use flag "--" to stop switch parsing
This creates an archive that does the following:
rsync::
(Everyone seems to like -z, but it is much slower for me)
-a: archive mode - rescursive, preserves owner, preserves permissions, preserves modification times, preserves group, copies symlinks as symlinks, preserves device files.
-H: preserves hard-links
-A: preserves ACLs
-X: preserves extended attributes
-x: don't cross file-system boundaries
-v: increase verbosity
--numeric-ds: don't map uid/gid values by user/group name
--delete: delete extraneous files from dest dirs (differential clean-up during sync)
--progress: show progress during transfer
ssh::
-T: turn off pseudo-tty to decrease cpu load on destination.
-c arcfour: use the weakest but fastest SSH encryption. Must specify "Ciphers arcfour" in sshd_config on destination.
-o Compression=no: Turn off SSH compression.
-x: turn off X forwarding if it is on by default.
Flip: rsync -aHAXxv --numeric-ids --delete --progress -e "ssh -T -c arcfour -o Compression=no -x" [source_dir] [dest_host:/dest_dir]
Lets you set all the java alternatives at once to a matching version. Also has options for just changing the jre or the plugin.
Also searches for aliases and shell builtins
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token.
This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use:
`awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'`
You must adapt the command line to include:
* $MFA_IDis ARN of the virtual MFA or serial number of the physical one
* TTL for the credentials
Find files and calculate size with stat of result in shell
