Linux Command Directory


Linux in a Nutshell

This directory of Linux commands is from Linux in a Nutshell, 5th Edition.

Click on any of the 687 commands below to get a description and list of available options. All links in the command summaries point to the online version of the book on Safari Bookshelf.

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makemap

makemap [options] type name

System administration command. Create database maps for use by sendmail in keyed map lookups. makemap will read from standard input and create a database file of type type with filename name.db. If the TrustedUser option is set in /etc/sendmail.cf and makemap is invoked as root, the ouput file will be owned by TrustedUser.

Input should be formatted as:

key value

Comment lines with #. Indicate parameter substitution with %n. Specify a literal % character by entering it twice: %%. The type may be btree or hash.

Options

-c size

Specify hash or B-Tree cache size.

-C file

Look up TrustedUser in the specified sendmail configuration file.

-d

Allow duplicate entries. Valid only with btree type maps.

-D x

Treat x as the comment marker instead of #.

-e

Allow empty value data fields.

-f

Suppress conversion of uppercase to lowercase.

-l

List supported map types.

-N

Append the zero-byte string terminator specified in sendmail's configuration file to mapped entries.

-o

Append to existing file instead of replacing it.

-r

If some keys already exist, replace them. (By default, makemap will exit when encountering a duplicated key.)

-s

Ignore safety checks.

-t delimiter

Use delimiter instead of whitespace.

-u

Undo a map: print out the specified database file, one entry per line.

-v

Verbose mode.


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