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Helping using sed

Hi,

I have a file that contains
aaaaa
bbbbb
aaaaa
eeeee
junk
more junk
end
I want to look for junk. Once i locate 'junk' i want to insert preferably a line of text (e.g "Here's more junk!") after the line 'junk'.

Can someone show me how to do this?

Thanks in advanced.

sed -e "/junk/a\Here's more junk!" junk

Nice introduction to sed ;)

Btw, I copied the contents of your file into a file called junk
that I fed to sed ;)
If you need the output in a new file you'll probably do something
like

Code:

sed -e "/junk/a\Here's more junk!" junk > new_junk

Code:

sed -e "/junk/a\Here's more junk!" junk | tee new_junk

Cheers,
Tink

Have you tried that command

Hi. Thanks for the response..

I tried the command you gave me and it's giving me this message:

sed: -e expression #1, char 9: Extra characters after command

is there something missing in your command,

sed -e "/junk/a\Here's more junk!" junk > new_junk

Also, sed will go through and put "Here's more junk!" after every instance of "junk" it finds. What if I only want to put that sentence after the 1st instance of the work "junk". I know you can used the line address for sed, but junk won't be on the same line every time.

Thx!

This what you are looking for? important parts in bold...

Skye

Quote:

[2addr]s/re/replacement/flags
Substitute the replacement string for the first instance of the
regular expression in the pattern space. Any character other
than backslash or newline can be used instead of a slash to de-
limit the RE and the replacement. Within the RE and the replace-
ment, the RE delimiter itself can be used as a literal character
if it is preceded by a backslash.

An ampersand (`&') appearing in the replacement is replaced by
the string matching the RE. The special meaning of `&' in this
context can be suppressed by preceding it by a backslash. The
string `\#', where `#' is a digit, is replaced by the text
matched by the corresponding backreference expression (see
re_format(7)).

A line can be split by substituting a newline character into it.
To specify a newline character in the replacement string, precede
it with a backslash.

The value of flags in the substitute function is zero or more of
the following:

0 ... 9
Make the substitution only for the N'th occurrence
of the regular expression in the pattern space.

Quote:

sed: -e expression #1, char 9: Extra characters after command

What does sed -V say?
The example works fine

Code:

GNU sed version 3.02.80

Did you copy & paste the example, or type it out?

As for the "only once" part ... I don't think that regexp
allow such a feature...

You'd have to go beyond a one-liner and feed
sed with a script that does the trick not with an
append, but rather with a substitution which (by
default, if you don't use the g-switch at the end)
will only replace the first occurence.
You'd be doing something like
[code]
s|junk|junk\nHere's more junk!|
[/ocde]

Cheers,
Tink

P.S.: You should really read the tutorial I posted ;)