Execute a command against one or more files in a header aware fashion.
The first line of each file is assumed to be a header. The first header
is output unchanged. Remaining lines are sent to the given command via
standard input, excluding the header lines of subsequent files. Output
from the command is appended to the initial header line.
A double dash (--) delimits the command, similar to how the pipe
operator (|) delimits commands. Examples:
$ keep-header file1.txt -- sort
$ keep-header file1.txt file2.txt -- sort -k1,1nr
These sort the files as usual, but preserve the header as the first line
output. Data can also be read from from standard input. Example:
$ cat file1.txt | keep-header -- grep red
-V --version Print version information and exit.
-h --help This help information.