Up Next Previous

Here Documents

This type of redirection instructs the shell to read input from the current source until a line containing only word (with no trailing blanks) is seen. All of the lines read up to that point are then used as the standard input for a command.

The format of here-documents is as follows:

.nf <<\fP[-\fP]word\fP here-document\fP delimiter\fP .fi
No parameter expansion, command substitution, arithmetic expansion, or pathname expansion is performed on .IR word . If any characters in word are quoted, the delimiter is the result of quote removal on .IR word , and the lines in the here-document are not expanded. If word\fP is unquoted, all lines of the here-document are subjected to parameter expansion, command substitution, and arithmetic expansion. In the latter case, the character sequence \<newline> is ignored, and \ must be used to quote the characters .BR \ , .BR $ , and .BR ` .

If the redirection operator is .BR <<- , then all leading tab characters are stripped from input lines and the line containing .IR delimiter . This allows here-documents within shell scripts to be indented in a natural fashion.

Up Next Previous

Web:  http://shell.tjgy.com
Email:support@tjgy.com