Sed & Awk (was: Re: Printf - Columns/Tables)
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From: Sidney Lambe on 29 Mar 2010 04:31 On comp.unix.shell, Ed Morton <mortonspam(a)gmail.com> wrote: > On 3/28/2010 2:42 PM, Sidney Lambe wrote: >> On comp.unix.shell, Ed Morton<mortonspam(a)gmail.com> wrote: >>> On 3/27/2010 9:28 PM, Sidney Lambe wrote: [delete awk propaganda from a fanatic] Sed and /bin/printf can do anything awk can do and are less than half the size combined. (Referring to gawk-3.1.1). They are fun to use and awk is way too complex for such a limited tool. Sid
From: bsh on 29 Mar 2010 20:22 Sidney Lambe <sidneyla...(a)nospam.invalid> wrote: > Ed Morton <mortons...(a)gmail.com> wrote: > > Sidney Lambe wrote: > > > Ed Morton<mortons...(a)gmail.com> wrote: > > > > Sidney Lambe wrote: > Sed and /bin/printf can do anything awk can do > and are less than half the size combined. (Referring > to gawk-3.1.1). Weeell.... While it is true that I have written a k/sh lexical scanner in sed(1) -- and BTW a parser in awk(1) -- and in doing so have gone far, far past the pale insofar as pertains to Lee E. McMahon's proforma of sed(1) introduced in v7 Unix of 1978 -- I wouldn't say that sed(1) is even remotely adapted to the kind of flow-of-control that n/g/awk(1) implements. Sure, there is a formal proof that there exists a sufficient Turing Machine to accomplish any decidable algorithm, but I wouldn't want to be the one to implement it! This is what non-trivial programming in sed(1) can feel like; I would rather program a moon landing in BASIC! (Check out "dc.sed" by Greg Ubben! http://sed.sf.net/grabbag/scripts/dc.sed http://sed.sf.net/local/scripts/dc.sed http://ppt.perl.org/commands/dc/dc.gsu "Overview Of How The dc.sed Script Works": sed.sf.net/grabbag/scripts/ dc_overview.htm ) > They are fun to use and awk is way too complex > for such a limited tool. Odd. I have tried for years to convince college professors of freshman programming in C, that starting with nawk(1) is a _much_ gentler introduction to programming than throwing them directly into *that* snakepit of a language. It's even quite efficient, if indeed that is a major criterion of language selection of sed(1) over nawk(1): http://cm.bell-labs.com/cm/cs/who/bwk/interps/pap.html =Brian
From: Sidney Lambe on 29 Mar 2010 21:46 On comp.unix.shell, bsh <brian_hiles(a)rocketmail.com> wrote: > Sidney Lambe <sidneyla...(a)nospam.invalid> wrote: >> Ed Morton <mortons...(a)gmail.com> wrote: >> > Sidney Lambe wrote: >> > > Ed Morton<mortons...(a)gmail.com> =A0wrote: >> > > > Sidney Lambe wrote: > >> Sed and /bin/printf can do anything awk can do >> and are less than half the size combined. (Referring >> to gawk-3.1.1). > > Weeell.... > > While it is true that I have written a k/sh lexical scanner > in sed(1) -- and BTW a parser in awk(1) -- and in doing > so have gone far, far past the pale insofar as pertains > to Lee E. McMahon's proforma of sed(1) introduced > in v7 Unix of 1978 -- I wouldn't say that sed(1) is even > remotely adapted to the kind of flow-of-control that > n/g/awk(1) implements. You aren't using just sed. You are using the shell, too. And I said sed and /bin/printf, not just sed. > Sure, there is a formal proof that there exists > a sufficient Turing Machine to accomplish any > decidable algorithm, but I wouldn't want to be the > one to implement it! This is what non-trivial > programming in sed(1) can feel like; I would > rather program a moon landing in BASIC! That's why you keep these scripts in an organized archive so that you can use them as templates when similar need arise. For a simple example, I don't type this every time I need it. It's in a file: 's/\(\)\(\)\(\)\(\)\(\)\(\)\(\)\(\)\(\)\(\)\(\)\(\)\(\)\(\)//' or: 'y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/' > > (Check out "dc.sed" by Greg Ubben! > http://sed.sf.net/grabbag/scripts/dc.sed > http://sed.sf.net/local/scripts/dc.sed > http://ppt.perl.org/commands/dc/dc.gsu > "Overview Of How The dc.sed Script Works": sed.sf.net/grabbag/scripts/ > dc_overview.htm > ) > >> They are fun to use and awk is way too complex >> for such a limited tool. > > Odd. I have tried for years to convince college > professors of freshman programming in C, that > starting with nawk(1) is a _much_ gentler > introduction to programming than throwing > them directly into *that* snakepit of a language. > > It's even quite efficient, if indeed that is a major > criterion of language selection of sed(1) over > nawk(1): > > http://cm.bell-labs.com/cm/cs/who/bwk/interps/pap.html > >=3DBrian You know, I am talking about ordinary usage. Not trying to use sed for NASA engineering projects. Sid
From: bsh on 30 Mar 2010 20:01 Sidney Lambe <sidneyla...(a)nospam.invalid> wrote: > bsh <brian_hi...(a)rocketmail.com> wrote: > > Sidney Lambe <sidneyla...(a)nospam.invalid> wrote: > > > Ed Morton <mortons...(a)gmail.com> wrote: > > > > Sidney Lambe wrote: > > > > > Ed Morton<mortons...(a)gmail.com> =A0wrote: > > > > > > Sidney Lambe wrote: > You aren't using just sed. You are using the shell, too. > And I said sed and /bin/printf, not just sed. You don't have to be combative; I understand the context. (And no, I am _not_ using the shell too: the scanner/parser scripts I was mentioning are actions within a makefile, and are directly exec'ed without the intervention of the shell). > You know, I am talking about ordinary usage. Not trying > to use sed for NASA engineering projects. Neither are freshmen in their first C programming class. =Brian
From: Sidney Lambe on 30 Mar 2010 21:53
On comp.unix.shell, bsh <brian_hiles(a)rocketmail.com> wrote: > Sidney Lambe <sidneyla...(a)nospam.invalid> wrote: >> bsh <brian_hi...(a)rocketmail.com> wrote: >> > Sidney Lambe <sidneyla...(a)nospam.invalid> wrote: >> > > Ed Morton <mortons...(a)gmail.com> wrote: >> > > > Sidney Lambe wrote: >> > > > > Ed Morton<mortons...(a)gmail.com> =A0wrote: >> > > > > > Sidney Lambe wrote: > >> You aren't using just sed. You are using the shell, too. >> And I said sed and /bin/printf, not just sed. > > You don't have to be combative; I understand the context. No. You don't. > (And no, I am _not_ using the shell too: the scanner/parser > scripts I was mentioning are actions within a makefile, and are > directly exec'ed without the intervention of the shell). I obviously wasn't talking about your scripts. I was talking about using sed and printf with the shell. >> You know, I am talking about ordinary usage. Not trying >> to use sed for NASA engineering projects. > > Neither are freshmen in their first C programming class. > >=Brian Good grief. Sid |