07-28-2005
operator '>' connects a program to a file, whicle '|' connect a program to another program (by making first one's stdout as second's stdin). this command should do what you're trying:
man mail | grep "delete" > delete
what happens is, man echoes the contents of corresponding manual page to stdout. executed with no input files, grep expects input from stdin (usually keyboard, but in this case, because of the pipe character '|', stdin is "man mail"'s stdout). then grep's output is directed to the file named delete.
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LEARN ABOUT DEBIAN
debconf-set-selections
DEBCONF-SET-SELECTIONS(1) Debconf DEBCONF-SET-SELECTIONS(1)
NAME
debconf-set-selections - insert new default values into the debconf database
SYNOPSIS
debconf-set-selections file
debconf-get-selections | ssh newhost debconf-set-selections
DESCRIPTION
debconf-set-selections can be used to pre-seed the debconf database with answers, or to change answers in the database. Each question will
be marked as seen to prevent debconf from asking the question interactively.
Reads from a file if a filename is given, otherwise from stdin.
WARNING
Only use this command to seed debconf values for packages that will be or are installed. Otherwise you can end up with values in the
database for uninstalled packages that will not go away, or with worse problems involving shared values. It is recommended that this only
be used to seed the database if the originating machine has an identical install.
DATA FORMAT
The data is a series of lines. Lines beginning with a # character are comments. Blank lines are ignored. All other lines set the value of
one question, and should contain four values, each separated by one character of whitespace. The first value is the name of the package
that owns the question. The second is the name of the question, the third value is the type of this question, and the fourth value (through
the end of the line) is the value to use for the answer of the question.
Alternatively, the third value can be "seen"; then the preseed line only controls whether the question is marked as seen in debconf's
database. Note that preseeding a question's value defaults to marking that question as seen, so to override the default value without
marking a question seen, you need two lines.
Lines can be continued to the next line by ending them with a "" character.
EXAMPLES
# Force debconf priority to critical.
debconf debconf/priority select critical
# Override default frontend to readline, but allow user to select.
debconf debconf/frontend select readline
debconf debconf/frontend seen false
OPTIONS
--verbose, -v
verbose output
--checkonly, -c
only check the input file format, do not save changes to database
SEE ALSO
debconf-get-selections(1) (available in the debconf-utils package)
AUTHOR
Petter Reinholdtsen <pere@hungry.com>
2012-09-10 DEBCONF-SET-SELECTIONS(1)