This: date +%s will return the number of seconds since the epoch. This: date +%s%N returns the seconds and current nanoseconds. So: date +%s%N | cut -b1-13 will give you the number of milliseconds since the epoch – current seconds plus the left three of the nanoseconds. and from MikeyB – echo $(($(date +%s%N)/1000000)) (dividing … Read more
To change the passphrase on your default key: $ ssh-keygen -p If you need to specify a key, pass the -f option: $ ssh-keygen -p -f ~/.ssh/id_dsa then provide your old and new passphrase (twice) at the prompts. (Use ~/.ssh/id_rsa if you have an RSA key.) More details from man ssh-keygen: […] SYNOPSIS ssh-keygen [-q] … Read more
The ‘c’ means it’s a character device. tty is a special file representing the ‘controlling terminal’ for the current process. Character Devices Unix supports ‘device files’, which aren’t really files at all, but file-like access points to hardware devices. A ‘character’ device is one which is interfaced byte-by-byte (as opposed to buffered IO). TTY /dev/tty … Read more
Looks like your $pathname includes more than one word. Could be multiple lines in your .rm.cfg file, or perhaps the path includes spaces. Anyway, you end up with which is no good. If you’re just expecting a single path and want to protect against the path containing whitespace, change your if line to
The -i flag specifies the private key (.pem file) to use. If you don’t specify that flag (as in your first command) it will use your default ssh key (usually under ~/.ssh/). So in your first command, you are actually asking scp to upload the .pem file itself using your default ssh key. I don’t … Read more
Underneath the file system, files are represented by inodes. (Or is it multiple inodes? Not sure.) A file in the file system is basically a link to an inode.A hard link, then, just creates another file with a link to the same underlying inode. When you delete a file, it removes one link to the … Read more
There are several ways, but using rename will probably be the easiest. Using one version of rename: Using another version of rename (same as Judy2K’s answer): You should check your platform’s man page to see which of the above applies.
Tell grep to treat your input as fixed string using -F option. Option -n is required to get the line number,
an example to send attachment and to send attachment AND write the message body
Enter super user mode, and cd into the directory that you are not permissioned to go into. Sudo requires administrator password.