Re: [ast-users] trap issue
Thanks for your reply!
WRT "ERR"; you're right, and I shouldn't have mentioned POSIX here
since in most cases I anyway care only about the prominent shells,
i.e. [AST] ksh, bash, and zsh, where ERR is supported. Sorry for my
misleading formulation!
I am aware how to interrogate exit status of individual commands,
that was not the point here. I want to catch and remap _all_ errors
using a handler. So I was astonished that ksh - as opposed to bash
and zsh! - doesn't seem to behave correctly, or at least not as I'd
have expected.
Elsewhere I've been proposed installing an EXIT handler and emulate
the ERR handling on my own, like this:
sig_was_caught=
sig_handler()
{
sig_was_caught=y
exit 9
}
exit_handler()
{
saved_status=$?
if [ $sig_was_caught ] ; then
printf "Execution aborted!\n"
exit $saved_status
elif [ $saved_status -ne 0 ] ; then
printf "An error occurred!\n"
exit 8;
fi
}
that's fine but a bit bulky, and I'd prefer using a simple ERR trap
which *does* work correctly (or as expected) in bash and zsh.
But maybe I'm missing something...?
Janis
Von: Bruce Lilly <bruce.li...@gmail.com>
Gesendet: Donnerstag, 27. April 2017 22:51
An: Janis Papanagnou
Cc: ast-us...@research.att.com
Betreff: Re: [ast-users] trap issue
trap ... ERR isn't recognized by NetBSD (supposedly POSIX-compliant) /bin/sh,
so any script using that won't run under that shell.
Specific commands' return status can be used to detect errors, e.g.:
some_command
if test 0 -ne $? ; then printf "some_command failed\n" ; exit 8 ; fi
or more simply:
some_command || ( printf "some_command failed\n" ; exit 8; )
It's possible to encapsulate the equivalent of your ERR trap as a function
(but note that the NetBSD /bin/sh only groks Bourne shell function
definitions), e.g.:
error_handler() { printf "An error occurred!\n"; exit 8; }
...
some_command || error_handler
Without the ERR trap, signal traps plus the above (ERR isn't a signal)
should work with most signals and shells. But unless you like core
dumps, don't trap CHLD if running with pdksh or mksh...
If you forego compatibility and use ERR, you can avoid triggering it
for some specific commands by using a command list guaranteed to
return 0 status, e.g.:
{ sleep 10 || true;} # N.B. opening brace must be the first character on the
line
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
[ast-users] Location of ksh man pages?
It seems the man pages for ksh88/ksh93 vanished from kornshell.com/doc for some time now. Is there a new location where the official documents can be got from? Janis ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] ksh - printf '%R'
On Saturday, June 13, 2015 06:59:21 AM Janis Papanagnou wrote: It seems that ksh's printf %R is producing wrong results for negated glob-patterns: $ printf %R\n !(*bak) ^(.*bak)!$ $ echo $'abc\nabcbak\ndef' | grep -E '^(.*bak)!$' ...empty result... [...] Is a regex equivalent to !() possible at all using any typical set of features? Since negative lookbehind generally doesn't support quantifiers I've never found a working solution even using fancy regex dialects. It likely requires conditional regex and some tricky use of (?R), if it's possible at all. Yes, it's possible, just not as trivial as with the simple other forms (*, +, ?), where you can apply a (mechanical) one-to-one mapping and only have to consider anchors. (Someone recently explained it based on an example, but currently I cannot find that Usenet(?) or StackExchange(?) posting.) You actually need to break the simple form !(...) into a sequence of variants of sub-regexps with negated character classes. Specificall there's no look-behind (or similar) necessary to achieve that. The transformation is not trivial and error-prone to do by hand, so an automatism (one that works) like the above mentioned %R would have been really nice, specifically for the negation. -- Dan Douglas ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
[ast-users] ksh - printf '%R'
It seems that ksh's printf %R is producing wrong results for negated glob-patterns: $ printf %R\n !(*bak) ^(.*bak)!$ $ echo $'abc\nabcbak\ndef' | grep -E '^(.*bak)!$' ...empty result... I'm aware that a conversion of a negation glob to regexp is not trivial to implement, but I'd like to know: Is this a known issue, and are there plans to fix that? Thanks! ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Accuracy of FP arithmetics
Ben, what ksh version are you using (and on what system)?
$ print $(( log(1000)/log(10)+1 ))
4
$ ksh --version
version sh (ATT Research) 93u+ 2012-08-01
This is on a 64 bit Linux 3.2.0
From: balt...@air.org
To: janis_papanag...@hotmail.com; ast-us...@research.att.com
Subject: RE: [ast-users] Accuracy of FP arithmetics
Date: Fri, 15 May 2015 12:13:08 +
$ print $(( log(1000)/log(10)+1 ))
3.99961
$ print $(( int(log(1000)/log(10))+1 ))
3
Ben
From: ast-users-boun...@lists.research.att.com
[mailto:ast-users-boun...@lists.research.att.com]
On Behalf Of Janis Papanagnou
Sent: Friday, May 15, 2015 6:23 AM
To: ast-us...@research.att.com
Subject: [ast-users] Accuracy of FP arithmetics
This is a question of *how* does it ksh *right* where other tools (awk) fail.
The task was to get the number of digits in a decimal number. (N.B.: the log()
division was used instead of log10() because of the latter's unavailability in
awk.)
$ awk 'BEGIN {print (log(999)/log(10))+1}'
3.99957
$ awk 'BEGIN {print (log(1000)/log(10))+1}'
4
Adding an int() call to above functions:
$ awk 'BEGIN {print int(log(999)/log(10))+1}'
3
$ awk 'BEGIN {print int(log(1000)/log(10))+1}'
3
The last result is wrong (due to internal rounding/accuracy problems in FP
arithmetics [see Goldberg's paper on FP arithmetics]).
Contrary to awk, ksh correctly does (without and with the int() call):
$ echo $(( log(1000)/log(10)+1 ))
4
$ echo $(( int(log(1000)/log(10))+1 ))
4
I'm assuming that both tools, awk and ksh, use C library functions for FP
arithmetic. - What does ksh internally do to create a correct result?
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Problem with ksh read -n
Thanks for you explanations! - My notes below... Date: Tue, 17 Mar 2015 17:19:24 -0500 From: terrence.j.doyle+...@gmail.com There are two points, here. First, you're using an old version of ksh. Yes, I'm aware and noted that myself. I'd be happy if newer ksh's behaviour would not only be different than older ksh's, but also... (see below) Second, ksh has a different spin from bash on reading fixed-length data. Read sees variables in two flavors, text and binary. I'm in this case primarily interested in text. When read puts characters into a textual variable newlines are always changed to a null character which serves as a string terminator. Also, when ksh reads fixed-length data, characters continue to fill the buffer after a newline is read. Thus, any characters read into your line variable after a newline will effectively disappear. Diasappearing characters when processing ordinary text is what annoys and surprises me; also conceptually. The man page says: The -n option causes at most n bytes to read rather a full line but will return when reading from a slow device as soon as any characters have been read. No mention of discarding any characters. (And why would that make more sense than reading up to the desired amount, and keep the rest for another read.) (And I didn't specify -N, to read exactly an amount of characters, I called it with -n, to read at most the given amount of characters.) When I run your test with ksh-20140929, I get these results: 'ABCDEFGHIJ123456' '7890' '234567890' (Frankly, this shocks me even more than the output I got from that older ksh version I used.) The first 16 characters are put into line as expected and printf %s displays them. In the next loop iteration read puts another 16 characters into line but changes the newline to a null character. Printf %s sees the null character as end-of-string and prints only 7890. That's fine and as expected. Characters 6 through 16 (abcdefghij1) in line can't be seen using printf %s. Here I see the problem. According to read's option -n, it should not read more than the 6 characters (i.e. insert a NUL, and then another string of chracters). Rather it should read just 6 characters and aborting the read while skipping the NL and terminating the string internally with NUL. So that the rest is available for the next read. In the final iteration the remaining characters are put in line and printf %s displays them. If you don't want ksh to change newlines to null characters in fixed-length data, you need to use binary variables. No, what I would want is that there's not more characters read than asked for. All the features related to binary processing is not what I wanted; I just want to do (non-binary, printable characters) text processing. Binary variables are declared with typeset -b. To print binary variables you should use printf %B. As with textual variables read will continue to fill the buffer after a newline is read. I modified your example for binary variables as follows: typeset -b line while IFS= read -n16 -r line do printf -- '%B'\n line done EOT ABCDEFGHIJ1234567890 abcdefghij1234567890 EOT This produced the following output: 'ABCDEFGHIJ123456' '7890 abcdefghij1' '234567890 ' (A change to binary processing is not what I wanted to achieve, so the results of your changes naturally don't reflect the expected outcome.) It might be more appropriate to change line to buffer to go along with ksh's behavior. It's still different from bash, but I'm content letting ksh be ksh and bash be bash. To be clear; it's *not* about ksh imitating bash. It's about a behaviour of ksh's read that's (IMO) extremely surprising (and [IMO] not helpful). I don't know if the new bash compatability-mode makes reading fixed-length data closer to bash's style. I'm not a bash user (usually), I very much prefer ksh. But methinks the visible behaviour of read -n is not intuitive, specifically when it comes to silently discarding characters. The explanations here left me with a feeling that read -n behaves the way it is because it's technically implemented in the way it is. Not really satisfying. But thanks again. - More insights about why the given read -n behaviour is more sensible than bash's (in this specific read -n case) is welcome. Terrence Doyle On 3/15/15 9:10 AM, Janis Papanagnou wrote: I observe a problem (see testcase below) with ksh's read -n. (Version 93t 2008-11-04 on Cygwin). Bash's behaviour would be what I expect. Ksh doesn't read the second line and doesn't terminate output. (Maybe an old bug fixed in newer versions? Or am I missing something?) --snip-- $ cat readtest while IFS= read -n16 -r line do printf '%s'\n $line done EOT ABCDEFGHIJ1234567890 abcdefghij1234567890 EOT $ bash readtest | head 'ABCDEFGHIJ123456
[ast-users] Problem with ksh read -n
I observe a problem (see testcase below) with ksh's read -n. (Version 93t 2008-11-04 on Cygwin). Bash's behaviour would be what I expect. Ksh doesn't read the second line and doesn't terminate output. (Maybe an old bug fixed in newer versions? Or am I missing something?) --snip-- $ cat readtest while IFS= read -n16 -r line do printf '%s'\n $line done EOT ABCDEFGHIJ1234567890 abcdefghij1234567890 EOT $ bash readtest | head 'ABCDEFGHIJ123456' '7890' 'abcdefghij123456' '7890' $ ksh readtest | head 'ABCDEFGHIJ123456' '7890' '' '' '' '' '' '' '' '' $ ksh --version version sh (ATT Research) 93t 2008-11-04 --snip-- ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] how to get functionality of bash compatible PS1 without rest of bash compatibility?
Well, I'll abstain from diving into your code; you're right, it's quite ugly.
:-)
For the date calculations part of your question the easiest may be to use some
builtins.
The following create the current date and the date t0 from the current day,
both in seconds...
t_now_s=$( printf %(%s)T\n )
t0_s=$( printf %(%s)T\n $(date +%Y) )
seconds_diff=$(( t_now_s - t0_s ))
(Maybe it's even easier than that to achieve, but I think this is already more
legible then what you have.)
Subject: Re: [ast-users] how to get functionality of bash compatible PS1
without rest of bash compatibility?
From: rlham...@gmail.com
Date: Thu, 12 Mar 2015 17:26:58 -0400
CC: ast-users@lists.research.att.com
To: janis_papanag...@hotmail.com
My code does NOT attempt to provide bash PS1 compatibility, it just plugs in a
time and truncated (leading levels) directory; the time is based on a computed
offset since midnight to add to SECONDS, so it doesn’t need to run builtins
when PS1 is evaluated. It works, and the performance isn’t horrible, but it’s
ugly beyond all recognition.
Some of it’s mine, some of it (the directory part for sure; can’t remember
whether the start of the time code was mine or a scrounge) is scrounged.
Basically I make a PS0 that will later (within function _cd) become part of PS1.
Before, I actually reset SECONDS to be seconds since midnight, but I recently
changed it to be an offset added to SECONDS, so as to leave SECONDS unaltered
and be able to stick it in PS4 along with a set -x at the top of my .profile,
trying to track down an annoying variation from 1 sec to 10 sec in how long
it takes to start a new login shell.
cd is aliased to function _cd, which runs real ‘cd’ and diddles the path part
of PS1.
Here’s the PS0 (time) part: eval export _offset=$(( $(/bin/date
'+3600*%H+60*%M+%S') - ${SECONDS} )) _pad[1]=0;_pad[2]=''
_hh=((SECONDS+${_offset})/3600)%24 _mm=((SECONDS+${_offset})/60)%60
_ss=((SECONDS+${_offset}))%60
_time='${_x[(_m=_mm)==(_h=_hh)==(_s=_ss)]}${_pad[${#_h}]}$_h:${_pad[${#_m}]}$_m:${_pad[${#_s}]}$_s'
PS0=$_time[!]${_hostname%%.*}:
Like I said, I don’t even really understand the line starting with _time=
anymore. The _pad[] part I understand, but not the _x[] part, although I think
that might have been a way to cause the evaluation to happen as I needed it to.
Within _cd, PS1 finally gets set as follows: if (( ${#PWD} 15 ))
thent1=${PWD%/*???}t2=${PWD#$t1/}
if (( ${#PWD} ( ${#t2} + 3 ) ))then
PS1=${label}$PS0...${t2}${p} else
PS1=${label}$PS0$PWD${p} fi else
PS1=${label}$PS0$PWD${p} fi
$label is (depending on the terminal type) an escape sequence to incorporate
the hostname and current directory into the window title bar. To keep that
from confusing ksh’s idea of display column, it ends with a ^M.
It all works, but the ugliness is OTT. There’s got to be a better way…
On Mar 12, 2015, at 8:51 AM, Janis Papanagnou janis_papanag...@hotmail.com
wrote:To understand your situation...
You have already functional code?
Your code works but it has a performance problem building the PS1 prompt?
If you want something cleaner and faster it would help if you post your
code so that we see where you are.
From: rlham...@gmail.com
Date: Thu, 12 Mar 2015 08:20:42 -0400
To: ast-users@lists.research.att.com
Subject: [ast-users] how to get functionality of bash compatible PS1 without
rest of bash compatibility?
Yep, that was the question: more or less bash-compatible PS1 handling without
the rest of bash compatibility. I like timestamps and other odd things
(shortened directory) in my prompt, but I’d rather do it without enabling any
more bash compatibility than that. I’ve got some odd code that even I no
longer understand that gives the output I want, but it’s very ugly (certainly
not using a get discipline or anything like that, but computing a date having
determined an offset to apply to SECONDS to count since midnight). Something
cleaner and faster might be nice.
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
[ast-users] Order of arguments significant with heredocs and process substitution?
Is the error in case 4 intentional behaviour...? # case 1 - okay cat - EOT | ... EOT awk '1' ( ... ) - # case 2 - okay awk '1' ( ... ) - EOT ... EOT # case 3 - okay awk '1' ( ... ) EOT - ... EOT # case 4 - error: `)' unexpected awk '1' EOT ( ... ) - ... EOT # case 5 - okay print ... infile awk '1' EOT infile - ... EOT Observed with version sh (ATT Research) 93t+ 2010-03-05 Is this inconsistency fixed in newer versions of ksh (or is it intentional behaviour)? Thanks! ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] making wildcards safer
You are asking: Has this already been considered and rejected for reasons of which I'm unaware, or does it sound reasonable to others? As far as a quick view over the linked document can show I have got the impression that the mentioned problems arise where '--' is not used (or not available?) when using commands to mark the 'end of options'. When you're unsure about what files are or can be present in your processed directories you should place a '--' after the option list and before the wildcards appear. From the POSIX Utility Guidelines: Guideline 10:The first -- argument that is not an option-argument should be accepted as a delimiter indicating the end of options. Any following arguments should be treated as operands, even if they begin with the '-' character. From: rlham...@gmail.com Date: Fri, 11 Jul 2014 21:39:32 -0400 To: ast-users@lists.research.att.com Subject: [ast-users] making wildcards safer I recently read http://www.defensecode.com/public/DefenseCode_Unix_WildCards_Gone_Wild.txt and although I was not unaware of these possibilities, the reminder was nonetheless uncomfortable. It occurred to me that most abuses of wildcards with filenames that a command might interpret as something other than a filename can be prevented by preceding any wildcard that starts with a metacharacter with ./. It is not impossible to train oneself to type ./* instead of *...but it's not particularly easy, either. It then occurred to me that it would be great to have a shell option something like set -o saferexpand which would do just that: precede any results of the expansion of a wildcard whose first character was a metacharacter with ./. For compatibility, it should be an option; and for the immediate future, not the default. Has this already been considered and rejected for reasons of which I'm unaware, or does it sound reasonable to others? ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] A real number arithmetic issue
I have to followup on my own post from last week. The proposed new version of ksh that I installed has a horrible side effect when using the interactive history functions in vi mode; misplacing the cursor, displaying control code, and thus making it impossible to use. (I'm working on 64 bit Linux.) Has someone observed a similar behaviour? I switched back to the 2010 version and the history fine again; modulo that real number bug - but I can do arithmetic using other tools, still better than a spoiled history function. From: janis_papanag...@hotmail.com To: ast-users@lists.research.att.com Date: Fri, 27 Jun 2014 10:58:28 +0200 Subject: Re: [ast-users] A real number arithmetic issue Yes, indeed, four years is obviously too old. :-) I downloaded the binary from http://www2.research.att.com/sw/download/ and can confirm your results from the test case. Just wondered that the latest precompiled binary for a standalone ksh is also quite old (2012-08-06 BASE linux.i386-64); is above download link still valid? - I noticed you are using a 2014 version. Thanks! Date: Thu, 26 Jun 2014 14:48:27 -0400 Subject: Re: [ast-users] A real number arithmetic issue From: dgk...@gmail.com To: janis_papanag...@hotmail.com; ast-users@lists.research.att.com I suspect that this is because you are running a very old ksh93. Here is what I get on ubuntu linux x86_63.13.0-30-generic4 release . [...] On Wed, Jun 25, 2014 at 3:59 PM, Janis Papanagnou janis_papanag...@hotmail.com wrote: I've just noticed something strange with real number arithmetic in ksh. The problem: It seems that the fractional part in a division is interpreted as integer. [...] All done in the LC_ALL=C locale. On a Linux 2.6 platform. Am I doing something wrong or is this some shell issue? Thanks! ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
[ast-users] A real number arithmetic issue
I've just noticed something strange with real number arithmetic in ksh. The problem: It seems that the fractional part in a division is interpreted as integer. $ print $(( log(2.171828) )) 0.775569209249095711 $ print $(( log(200.0) / log(2.171828) )) ksh: log(200.0) / log(2.171828) : divide by zero $ print $(( log(200.0) / log(2) )) ksh: log(200.0) / log(2) : divide by zero $ print $(( log(200.0) / log(3) )) 14 $ typeset -F a=200 $ typeset -F b=2.71828 $ print $(( log(a) / log(b) )) ksh: log(a) / log(b) : divide by zero $ print $a $b 200.00 2.718280 $ typeset -F b=3.0 $ print $(( log(a) / log(b) )) 14 $ printf %f\n $(( log(a) / log(b) )) 14.00 $ typeset -F b=3.1 $ printf %f\n $(( log(a) / log(b) )) 14.00 $ ksh --version version sh (ATT Research) 93t+ 2010-03-05 All done in the LC_ALL=C locale. On a Linux 2.6 platform. Am I doing something wrong or is this some shell issue? Thanks! ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Strange printf %T behaviour
From: iszczesn...@gmail.com To: janis_papanag...@hotmail.com CC: ast-us...@research.att.com; glenn.s.fow...@gmail.com On Sat, Apr 5, 2014 at 12:24 PM, Janis Papanagnou janis_papanag...@hotmail.com wrote: Please note the empty output lines of commands that previously showed output... $ printf %(%Z)T\n CEST $ TZ=GMT printf %(%Z)T\n GMT $ printf %(%Z)T\n CEST $ TZ= printf %(%Z)T\n $ printf %(%Z)T\n $ TZ=UTC printf %(%Z)T\n $ printf %(%Z)T\n $ TZ=GMT printf %(%Z)T\n $ printf %(%Z)T\n Version JM 93t+ 2010-03-05 (on Linux 2.6.32) Is that a bug in the (old) ksh version I use, and fixed in the current one? Random thought: Any printf %argument requires an argument to be passed, so you want printf '%T' now instead of print '%T' Good point. But sadly adding 'now' doesn't change behaviour. Once the shell is in the no-output state it stays there without further output. Irek ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Configuring what goes into the history file
Omitting immediate duplicates as default seems reasonable to me. It would be simple, and need no additional external controls. Nice. Defining the beaviour through some means (env var or something) would allow more control variants; like omitting duplicates even if not adjacent in the file - the latter needs some more sophisticated implementation though. Or allow extensions to any of zsh's options (if considered useful). Beyond no immediate duplicates and no duplicates at all I'd have no need, but others might have, and it might be good to not rule out other options. Date: Fri, 3 Jan 2014 17:35:50 -0500 From: dgk...@gmail.com To: e...@horch.org CC: ast-users@lists.research.att.com Subject: Re: [ast-users] Configuring what goes into the history file Since all HISTCONTROL does is eliminate immediate duplicates or no keep commands that start with a space, I don't know why this can't be the default behavior. Ignoring failed commands seems like a bad idea. Failed command often occur because of a typo and in this case I want to edit the failed command. On Thu, Jan 2, 2014 at 8:47 PM, Ed Horch e...@horch.org wrote: What bash does is a good start. I've always wanted a more powerful way to exclude certain things from the command history, especially erroneous and failed commands. I haven't been able to think of a good way to specify that. For example: $ cat ~/.kshcr cat: /home/ebh/.kshcr: No such file or directory That shouldn't go into the history. But what about: $ cat ~/.kshrc cat: /home/ebh/.kshrc: No such file or directory $ echo 'alias l=ls\ -xF' ~/.kshrc $ # Would like to do M-PM-P here Maybe some keep-previous-command-anyway editing function or some such. -Ed Horch ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Configuring what goes into the history file
Subject: Configuring what goes into the history file. Yes, Ed, probably (I haven't checked bash). And I think zsh has something as well. But I am specifically asking for ksh, since that is the shell I mostly use. So I suppose there's no such feature in ksh? (And hardly a workaround, I guess.) @David: Are there any plans to incorporate such a feature? From: e...@horch.org Date: Thu, 2 Jan 2014 16:48:39 -0500 To: ast-users@lists.research.att.com Subject: Re: [ast-users] Configuring what goes into the history file That sounds like what bash's HISTCONTROL variable does. -Ed Horch ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Bad math for right shift () 64 bits?
Interested in the behaviour I tried that with my version (Version JM 93t+ 2010-03-05( and it gives the same result. Moreover I noticed that in integerb=$((2**32)) ; for ((i=0;i=97;i++)) ; do printf %5d\t%12d\n $i $(( b i )) ; done typeset -i b=$((2**32)) ; for ((i=0;i=97;i++)) ; do printf %5d\t%12d\n $i $(( b i )) ; done the first command produce the same result that you showed, while the second one produces only zeroes. Moreover, if I run the second command first (and get the zeroes), then run the first command I get also zeroes, and if I rund the second command a second time it produces the result you observed. Sorry, I meant if I run the _first_ command a second time: $ typeset -i b=$((2**32)) ; for ((i=31;i=33;i++)) ; do printf %5d\t%12d\n $i $(( b i )) ; done 31 0 32 0 33 0 $ integerb=$((2**32)) ; for ((i=31;i=33;i++)) ; do printf %5d\t%12d\n $i $(( b i )) ; done 31 0 32 0 33 0 $ integerb=$((2**32)) ; for ((i=31;i=33;i++)) ; do printf %5d\t%12d\n $i $(( b i )) ; done 31 2 32 1 33 0 So there even seems to be a dependency to some internal shell state. ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Raw command substitution $()
Can you exclude any character from your input data to be used as a separator?
Then you could redefine the read separator (in the example below I used X):
printf \n\n\n\n\n | IFS= read -dX FOO
Date: Mon, 16 Dec 2013 21:02:01 +
From: eschulm...@bloomberg.net
To: AST-USERS@LISTS.RESEARCH.ATT.COM
Subject: [ast-users] Raw command substitution $()
Hi guys,I'm looking for a method to do raw command substitution.
The issue:- Need a ksh93t+ / ksh93u facillity to be able to take the literal
output of a command with no substitutions or omissions, where the substitute
data is less than 1kB. Target platforms are RHEL 6.4, Solaris 11 AIX 7.1.
Examples. printf is used below for illustration only.- $(), command
substitution, i.e. FOO=$(printf \n\n\n\n\n); seems unsuitable as it modifies
the output by performing some whitespace handling, such as stripping newlines.
In this example, FOO returns zero-length.- $(), quoted, prevents the field
splitting and pathname expansions, but doesn't protect the trailing
whitespace.- Binary read, i.e. printf \n\n\n\n\n | read -N$length FOO;
works provided the $length of the read doesn't encounter the EOF, in this case
values 1-5. If $length5, in this example, FOO becomes zero-length. For an
input of unknown length, this feels impractical.- One possible workaround is
adding a suffix and then chopping it, i.e. FOO=$(printf
\n\n\n\n\nmysuffix); FOO=${FOO%mysuffix}
Any advice on the best way to acquire the literal command output?
Thanks!-G
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] operations on an entire array
Probably not as compact as you'd wish...
$ x=( 1 2 3 4 5 6 7 8 9 10 )
$ echo $(( $( printf +%d ${x[@]} ) ))
55
From: joshua.tay...@sub-verses.org
Date: Fri, 13 Dec 2013 14:53:24 +0100
To: ast-users@lists.research.att.com
Subject: [ast-users] operations on an entire array
I was wondering if there is some syntax or some method to perform an
operation (the same operation) on all elements of an array.
for example:
x=( 1 2 3 4 5 6 7 8 9 10 )
is there a shortcut to this:
((x[0]+x[1]+x[2]+x[3] ... )) as well as avoiding a for loop?
I had imagined something like x[@]+
Of course, if not, i’ve always got the classic:
for i in ${x[@]}
do
(( total=total+i ))
done
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Question about the nounset option
I understand the OP considering that clumsy. And something being defined
by POSIX doesn't prevent it being clumsy or not defined in an optimal way;
sometimes even the opposite is true. But I'd rather like to abstain from such
flame-prone valuations and consider the given application.
@Axel: I'm not sure your sample is only test code. If so, you can trigger the
effecte more simply (without if condition) by /bin/ksh -uc 'echo ${TESTVAR}'.
Otherwise I'd use the less clumsy /bin/ksh -uc 'echo ${TESTVAR-undefined}
(without if, but still with the default value substitution).
Part of the clumsiness in your sample stems from the explicit if test and the
implicit test in ${v- }; one can be avoided.
Janis
Date: Wed, 16 Oct 2013 14:23:57 +0200
From: lionelcons1...@gmail.com
To: axel.phil...@mtu.de
CC: ast-us...@research.att.com
Subject: Re: [ast-users] Question about the nounset option
On 16 October 2013 09:14, PHILIPP, Axel, Dr. axel.phil...@mtu.de wrote:
I wonder whether it is desirable that test -n and test -z trigger the unset
error condition:
/bin/ksh -uc 'if [[ -n $TESTVAR ]]; then echo $TESTVAR; else echo
undefined; fi'
/bin/ksh: TESTVAR: parameter not set
I know all shells from the sh family I have tested behave this way, but I
would prefer a solution (additional option or env var) that the error is
not triggered in these test cases.
You can use [[ -v TESTVAR ]] to test whether a variable does exists or
not. This uses the variables name (TESTVAR) and not the value
($TESTVAR).
The obvious workaround is somewhat clumsy:
/bin/ksh -uc 'if [[ -n ${TESTVAR-} ]]; then echo $TESTVAR; else echo
undefined; fi'
undefined
Why is this clumsy? This is how POSIX sh was designed and everyone
uses as designed. Why is this a problem?
Lionel
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Arithmetic assignment side-effects
Go strictly from left to right. How do you assign something that hasn't been evaluated yet? Evaluating the expression on the RHS is an absolute prerequisite to evaluating the assignment itself. (x += x) = 1 is nonsense. It evaluates to 0 = 1. It makes sense, depending on the language. With LVALUE=RVALUE and LVALUE+=LVALUE, where the result is an LVALUE, consider it evaluated as (ref(x) = deref(x)+deref(x)) = 1 (Try your expression above in C++, for example. It works as expected.) Nonetheless right to left parsing seems the only sensible semantics in case of = and op= assignments. Janis [...] I've also already proven that at least in ksh it goes right to left, because if you define a setter property to trigger a side-effect for each variable, the RHS fires before the LHS of the +=. There's just no amount of mind-bending I can think of that could make evaluating the += first produce anything other than an error. -- Dan Douglas ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Arithmetic assignment side-effects
Oops. Should have been... (x += x) = 1 is nonsense. It evaluates to 0 = 1. It makes sense, depending on the language. With LVALUE=RVALUE and LVALUE+=LVALUE, where the result is an LVALUE, consider it evaluated as LVALUE+=RVALUE (ref(x) = deref(x)+deref(x)) = 1 (Try your expression above in C++, for example. It works as expected.) Nonetheless right to left parsing seems the only sensible semantics in case of = and op= assignments. Janis ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Passing a file descriptor to a child process?
From: tina.harriott.mathemat...@gmail.com
On 29 July 2013 14:40, David Korn d...@research.att.com wrote:
cc: tina.harriott.mathemat...@gmail.com
Subject: Re: [ast-users] Passing a file descriptor to a child process?
ksh93 uses O_CLOEXEC to avoid passing all its file descriptors to a
child process. That is IMO a good thing (clean!).
However, is there a way to pass a file descriptor to a child process?
Tina
--
Tina Harriott - Women in Mathematics
Contact: tina.harriott.mathemat...@gmail.com
Yes, run
any_command {fd} foobar
to open foobar for reading and pass it to an_command.
exec {fd} foobar
will open it only in the shell environment
How can I keep the fd open for multiple commands in a sequence?
Command grouping...?
{ cmd1
cmd2
} {fd} foobar
Janis
Tina
--
Tina Harriott - Women in Mathematics
Contact: tina.harriott.mathemat...@gmail.com
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Edit 10GB file with fixed size records
Does ksh have an API to edit a file at a specific position pos1, read
n1 bytes, and write n1 bytes at that position without truncating the
file? I need this to do edit a file in place without reading and
writing it completely each time.
Yes, ksh has seek redirection operators.
[snip]
read -N $n1 content 0$f #((pos1))
printf %s $(fun $content) 1$f #((pos1))
[snip]
How would this example look like if I opened a file descriptor with
the number 19? ksh seems to use file descriptors 0-9 for manual usage,
but descriptors opened with exec {filed}name.rec use numbers 10.
I'd have thought by prepending {filed} to the seek redirections;
{filed}#((pos1)) and {filed}#((pos1)) respectively.
Doesn't that work?
Janis
Tina
--
Tina Harriott - Women in Mathematics
Contact: tina.harriott.mathemat...@gmail.com
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Can't pass parameters to an instance constructor
Hi, here x.val is assigned after the constructor has already run. It
should
be assigned before so it's accessiable to the create:
typeset -T X=( integer val
function create { ((_.val++)) })
X x=(val=5) print -v x.val # should print 6
ksh93 currently doesn't have a create discipline and you example doesn't
invoke x.create so why should val be incremented?
It's described within the TYPES document:
What is that document you mention and where can I find it?
And more generally; is there any detailled documentation of
ksh's new features besides the man page?
Thanks!
Janis
___
ast-users mailing list
ast-users@lists.research.att.com
http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] Check out my profile on LinkedIn
I'm very sorry for this. This is what I got for trusting that Linkedin only contacts people with existing Linkedin profiles. Your experience can be summarized... Abandon all hope, ye who enter here. [Dante] Ced ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] ksh88 vs 93 behavior re: hex numbers
With my ksh93 Version JM 93t+ 2010-03-05 I get what you expect $ typeset -i16 HEX=16#ff $ print $HEX 16# Date: Thu, 28 Feb 2013 18:43:52 -0800 From: patgeis...@gmail.com To: ast-users@lists.research.att.com Subject: [ast-users] ksh88 vs 93 behavior re: hex numbers All, Sorry if this is well-known but I searched through the list archives and didn't find anything on point. In short, ksh93 is masking off the upper bits of my hex numbers where ksh88 did not. My question is, is this by design? A bug? A LOCALE issue? If it's configurable, how do I get the old behavior back? ksh88 example: % typeset -i16 HEX=16#ff % print $HEX 16#ff ksh93 example: % typeset -i16 HEX=16#ff % print $HEX 16#7fff masked to lower 31-bits ... not what I want! __ Patrick ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
Re: [ast-users] [ksh93] interactive ksh always exits 0 on CTRL-D
Subject: Re: [ast-users] [ksh93] interactive ksh always exits 0 on CTRL-D Not a big problem but I think it better exit $?. I tried the following and it did not exit 0. $ ksh $ false ^D $ print $? 1 David Korn d...@research.att.com Do we need some specific ksh version to make that work? Or does that just mean that the behaviour is undefined? I am running ksh 93t+ 2010-03-05 and above sample as well returns 0 here in my Ubuntu/Linux 2.6 environment. (No traps set, BTW.) ___ ast-users mailing list ast-users@lists.research.att.com http://lists.research.att.com/mailman/listinfo/ast-users
