[Solved] bash expertise needed

Gen2ly · 2012-08-02 20:42:36

I got a array that I'd like to have expanded into multiple pipes and I can't think of anyway to do it. I'd like to do this:

exclude=(sandfox iso)

df -h | grep -e 'Avail' -e '^/dev' | grep -v sandfox | grep -v iso

I'd like the array to go into multiple versions of grep -v. Any thoughts on how to do this?

Last edited by Gen2ly (2012-08-03 00:22:44)

alphaniner · 2012-08-02 21:40:31

I can't say it's the ideal solution, but putting

grep -vf <(printf "%s\n" "${exclude[@]}")

after the second pipe should work. Assuming I'm understanding your snippet correctly, and you want to filter out any line containing anything from your array.

What it does: the printf command prints the array one item per line. The <( ... ) causes the output of the command inside it to be treated as a file. And the -f flag tells grep to obtain its patterns from this "file".

Last edited by alphaniner (2012-08-02 21:42:50)

jjacky · 2012-08-02 21:41:14

Far from a bash expert, but if I get what you're trying to do, a solution might be to put all your terms inside call to grep, e.g:

df -h | grep -e 'Avail' -e '^/dev' | egrep -v $(echo ${exclude[@]} | tr ' ' '|')

Procyon · 2012-08-02 22:13:03

You can control the array item separation character in bash.

When you use subscript * instead of @ and it is in double quotes, the first character of IFS is used.

IFS=$'\n'
df -h | grep -v "${exclude[*]}"

Gen2ly · 2012-08-02 23:22:38

alphaniner wrote:

I can't say it's the ideal solution, but putting
grep -vf <(printf "%s\n" "${exclude[@]}")
after the second pipe should work. Assuming I'm understanding your snippet correctly, and you want to filter out any line containing anything from your array.
What it does: the printf command prints the array one item per line. The <( ... ) causes the output of the command inside it to be treated as a file. And the -f flag tells grep to obtain its patterns from this "file".

You understood exactly what I was needing.

That is really neat. I never knew that in bash <( ... ) would treat it as a file. Very useful. Thank you.

Procyon wrote:

You can control the array item separation character in bash.
When you use subscript * instead of @ and it is in double quotes, the first character of IFS is used.
IFS=$'\n'
df -h | grep -v "${exclude[*]}"

I think this is a little different than I was looking for. But very good to know . Thanks Procyon.

jjacky · 2012-08-02 23:58:48

Procyon wrote:

When you use subscript * instead of @ and it is in double quotes, the first character of IFS is used.

Thank you for that! I knew there was a reason I couldn't get that to work (and used the ugly echo/tr), but had failed to find it (though I looked only briefly in man bash).

Arch Linux

#1 2012-08-02 20:42:36

[Solved] bash expertise needed

#2 2012-08-02 21:40:31

Re: [Solved] bash expertise needed

#3 2012-08-02 21:41:14

Re: [Solved] bash expertise needed

#4 2012-08-02 22:13:03

Re: [Solved] bash expertise needed

#5 2012-08-02 23:22:38

Re: [Solved] bash expertise needed

#6 2012-08-02 23:58:48

Re: [Solved] bash expertise needed

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