Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.debian.user > #178455

Re: Recomended tutoial(s) on doing arithmetic in Bash scripts

Show all headers | View raw

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Sun, Mar 05, 2017 at 12:10:43PM -0600, Richard Owlett wrote:

[...]

> How about the whole app <grin>
> You solved my problem with one line.

Glad it helped :)

[...]

> I needed to report the number of bytes downloaded for each portion
> of a project [...]

Let me pick a nit...

> mystring=$(echo $(grep "usb0" /proc/net/dev))

This should be equivalent to

  mystring=$(grep "usb0" /proc/net/dev)

(background:

  - grep "usb0"/proc/net/dev
    spits out the line(s) containing the pattern "usb0"

  - the $(...) around it expands it in the shell inline

  - the echo spits that again out to stdout

  - the $(...) around it expands it again in-line

So unless the expansion is doing anything funky (which we won't hope,
but see below), you can unwrap the outer $(echo ...).

Now the second nit: I'm not sure whether there's a case when the
unquoted $(...) might undergo a further expansion by the shell,
so it's prudent to quote it, like so:

  mystring="$(grep "usb0" /proc/net/dev)"

(I know, my example wasn't... exemplar in this respect, but I knew
I was only getting plain numbers and I was kind of lazy: bad tomás)

> Someone on another group wanted me to use LibreOffice Calc ;/

Might work, but don't ask me how :-/
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)

iEYEARECAAYFAli8c80ACgkQBcgs9XrR2kb3cwCfTzWmOlditJ0hK9vGMkpeJZQY
2BEAmwdhRnREpwGMQ9k8I1uS4jL10D9E
=+2Ss
-----END PGP SIGNATURE-----

Back to linux.debian.user | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Recomended tutoial(s) on doing arithmetic in Bash scripts Richard Owlett <rowlett@cloud85.net> - 2017-03-05 16:50 +0100
  Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Reco <recoverym4n@gmail.com> - 2017-03-05 17:30 +0100
  Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-05 17:30 +0100
    Re: Recomended tutoial(s) on doing arithmetic in Bash scripts GiaThnYgeia <GiaThnYgeia@openmailbox.org> - 2017-03-05 19:20 +0100
      Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-05 21:40 +0100
      Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Greg Wooledge <wooledg@eeg.ccf.org> - 2017-03-06 14:40 +0100
        Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-06 15:00 +0100
        Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Jörg-Volker Peetz <jvpeetz@web.de> - 2017-03-06 16:00 +0100
          Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-06 16:40 +0100
    Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Richard Owlett <rowlett@cloud85.net> - 2017-03-05 19:20 +0100
      Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Richard Owlett <rowlett@cloud85.net> - 2017-03-05 19:50 +0100
      Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-05 21:30 +0100
        Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Richard Owlett <rowlett@cloud85.net> - 2017-03-05 22:00 +0100
    Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Jude DaShiell <jdashiel@panix.com> - 2017-03-05 23:20 +0100
      Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Richard Owlett <rowlett@cloud85.net> - 2017-03-06 12:20 +0100
        Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-06 12:40 +0100
  Re: Recomended tutoial(s) on doing arithmetic in Bash scripts David Christensen <dpchrist@holgerdanske.com> - 2017-03-05 20:50 +0100
    Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Richard Owlett <rowlett@cloud85.net> - 2017-03-05 21:50 +0100
      Re: Recomended tutoial(s) on doing arithmetic in Bash scripts David Christensen <dpchrist@holgerdanske.com> - 2017-03-06 04:40 +0100
    Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-05 22:30 +0100
  Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Jude DaShiell <jdashiel@panix.com> - 2017-03-05 23:10 +0100

csiph-web