You can use ex
(which is a mode of the vi
editor) to accomplish this.
You can use the :read
command to insert the contents into the file. That command takes a filename, but you can use the /dev/stdin
pseudo-device to read from standard input, which allows you to use a <<EOF
marker.
The :read
command also takes a range, and you can use the $-
symbol, which breaks down into $
, which indicates the last line of the file, and -
to subtract one from it, getting to the second to last line of the file. (You could use $-1
as well.)
Putting it all together:
$ ex -s /etc/security/limits.conf -c '$-r /dev/stdin' -c 'wq' <<EOF
* soft nproc 65535
* hard nproc 65535
* soft nofile 65535
* hard nofile 65535
root soft nproc 65535
root hard nproc 65535
root soft nofile 65535
root hard nofile 65535
EOF
The -s
is to make it silent (not switch into visual mode, which would make the screen blink.) The $-r
is abbreviated (a full $-1read
would have worked as well) and finally the wq
is how you write and quit in vi
. :-)
UPDATE: If instead of inserting before the last line, you want to insert before a line with specific contents (such as "# End of file"), then just use a /search/
pattern to do so.
For example:
$ ex -s /etc/security/limits.conf -c '/^# End of file/-1r /dev/stdin' -c 'wq' <<EOF
...
EOF
# End of file
line there's probably no better way to make it work. Such tool would be eitherawk
orsed
. I'd recommend a 2 step process: delete the line viased -i '/# End of file/d'
and then insert the data you want with# End of file
added to originalcat
command you have there, or via third step -echo '# End of file' >> /etc/security/limits.conf
.