Linux in a Nutshell, Fifth Edition

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Chapter 10: The sed Editor

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Copyright © 2006 O’Reilly & Associates, Inc. All rights reserved.

T

[address1[,address2]]T [label] {G}

Like t, but only branches to label if there not any successful substi-

tutions. (see b, t, and

:). If label is not specified, control branches

to the bottom of the script.

v

[address1[,address2]]v [version] {G}

This command doesn’t do anything. You use it to require GNU sed

for your script. This works, because non-GNU versions of sed

don’t implement the command at all, and will therefore fail. If you

supply a specific version, GNU sed fails if the required version is

newer than the one executing the script.

w

[address1[,address2]]w file

Append contents of pattern space to file. This action occurs when

the command is encountered rather than when the pattern space is

output. Exactly one space must separate the w and the filename.

This command will create the file if it does not exist; if the file

exists, its contents will be overwritten each time the script is

executed. Multiple write commands that direct output to the same

file append to the end of the file.

GNU sed allows you to use the special filenames /dev/stdout and

/dev/stderr to write to standard output or standard error,

respectively.

Example

# Store HTML tables in a file

/<table/,/<\/table>/w tables.html

W

[address1[,address2]]W file

Like w, but only writes the contents of ...