what's the easiest, command-line way to remove all the commented lines in a shell script???

ack, not thinking....hold that thought.

For some reason, I'm pulling a brainfart on this...it's something I've done a few times, but now I can't remember how *sigh*, getting old can sometimes suck.

Ok, because, for the life of me, I can't remember how to do this in vi, here's a quick kludge. Assuming that, like most shells scripts, comments start out with a # as the first thing on the line, you can do this.

cat some_file | grep -v ^# > some_new_file

If someone can kickstart my brain and post the vi equivalent for this, I'd appreciate it.

This should do the trick (for vi, I mean)

:g/^#/d

The "easiest" command-line way might be:

grep -v ^# some_file

Arvind

thanks so much technoslave!!!

=)



i did this, as you suggested:


cat /etc/squid/squid.conf | grep -v ^# > /etc/squid/squid.conf.stripped


and it seems to have worked perfectly...

but now how would i go about removing the blank lines so that the remaining text is tightly arranged???

But at the same time you're removing the first line, which is an important part of the script.
You may want to do something like:

thanks!!!

thanks, good call.. i'd forgotten about the shebang, since i was trying this out on /etc/squid/squid.conf, which uses "#" for comments also but isn't a shell script, hence no shebang...

okay i think i found a way to remove the blank lines...

this (example) would make it so that there is no more than one blank line at a time (".stripped" means the comments have already been removed using cat and grep):


cat -s /etc/squid/squid.conf.stripped > /etc/squid/squid.conf.stripped.oneblank



and it seems this would get rid of the blank lines entirely (i googled a bit and found this here):


cat -s /etc/squid/squid.conf.stripped | sed '/^[[:space:]]*$/d' > /etc/squid/squid.conf.stripped.noblanks



do you know of a simpler way to do it, or is this pretty much it??

i'm wondering if "sed" is supposed to be a "standard" part of GNU (as i believe cat and grep to be), so as one could expect every distro to have sed...???

sorry for being such a newbie...

thanks so much for your input, i really appreciate it...

You want a way to get rid of all blank lines? This will do it:
tr -s "\n" </etc/squid/squid.conf.stripped

But, why do you want to struggle so much? How about this:
grep -v "^#" squid.conf | grep -v "^$" >/etc/squid/squid.conf.stripped.noblanks

Or even,
egrep -v "^#|^$" squid.conf >/etc/squid/squid.conf.stripped.noblanks

This would get rid of the temporary "stripped" file.

Don't get into the habit of using "cat" all over. Most commands take a filename or input can be piped in using "<", which will do what cat will, sometimes more efficiently. Look at: http://www.faqs.org/docs/jargon/U/UUOC.html or even http://rhols66.adsl.netsonic.fi/era/unix/award.html

Arvind

awesome!!! thanks!!!

=)



the "greps" from above do everything i need, but i'm curious about this "tr" cuz i can't seem to make it work...

after running it the file remains exactly the same (md5sum)...



whoa... thanks a million for that very good advice, and those very informative links...

"Useless Use of Cat Award"... lol... that was cool...

=)

Thanks from here too....I'd seen that in a few scripts but never understood its purpose

You're both welcome.

tr (short for translate) is just a filter. It's a filter in the truest sense of the word. It just filters it's input and writes it to stdout. What you want is probably something like:

It will not change the input file as it has no idea about it (that is, you're just piping the stripped file into it).

Arvind