how to create a non-ascii file using redirection with `sh -c`?
The same command: echo 1 > filename
creates different filenames:
$ sh -c 'echo $LANG >=с=.sh' && ls *.sh | od -c
0000000 = 321 = . s h \n
0000007
and
$ bash -c 'echo $LANG >=с=.bash' && ls *.bash | od -c
0000000 = 321 201 = . b a s h \n
0000012
Where с
is the U+0441
character — CYRILLIC SMALL LETTER ES. It is clear that sh
eats the second byte in the utf-8
encoding.
$ ls *sh
=?=.sh =с=.bash
$LANG
in both cases is:
$ cat *sh
en_US.utf8
en_US.utf8
sh
is linked to dash
on my system:
$ apt-cache show dash | grep -i version
Version: 0.5.5.1-7ubuntu1
stty iutf8
is set.
Is there any setting that allows dash
not to mangle multi-byte characters?
I don't see any mentions about character encoding in the manual:
$ man dash | grep -i encoding
$ man dash | grep -Pi 'multi.*byte'
Update
The second byte '\201'
of the 'с'
character in utf-8 encoding is
-127
as signed char (or 129
as unsigned char) in C.
The search in the source code (apt-get source dash
) for -127
results in:
src/parser.h:38:#define CTL_FIRST -127 /* first 'special' character */
src/parser.h:39:#define CTLESC -127 /* escape next character */
Search for CTLESC
leads to rmescapes()
macros that leads to the
following fragment from src/expand.c:expandarg()
:
/*
* TODO - EXP_REDIR
*/
if (flag & EXP_FULL) {
ifsbreakup(p, &exparg);
*exparg.lastp = NULL;
exparg.lastp = &exparg.list;
expandmeta(exparg.list, flag);
} else {
if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
rmescapes(p);
sp = (struct strlist *)stalloc(sizeof (struct strlist));
sp->text = p;
*exparg.lastp = sp;
exparg.lastp = &sp->next;
}
TODO
and XXX
hints that a more recent version might
help. debian/dash.README.source
points to:
$ git clone http://smarden.org/git/dash.git/
$ cd dash
There are two branches:
$ git br
* debian-sid
release+patches
On debian-sid
the escape byte is removed. On the release+patches
branch grep
finds the missing byte.
$ ./configure
$ make && rm *.dash -f; ./dash -c 'echo 1 >fсf.dash' &&
> ls *.dash | od -c | grep 201
git diff debian-sid...release+patches
shows that rmescapes()
was
removed in release-patches
:
diff --git a/src/expand.c b/src/expand.c
index e4c4c8b..f2f964c 100644
--- a/src/expand.c
+++ b/src/expand.c
...
@@ -213,8 +210,6 @@ expandarg(union node *arg, struct arglist *arglist, int flag)
exparg.lastp = &exparg.list;
expandmeta(exparg.list, flag);
} else {
- if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
- rmescapes(p);
sp = (struct strlist *)stalloc(sizeof (st开发者_开发技巧ruct strlist));
sp->text = p;
*exparg.lastp = sp;
@@ -412,7 +407,7 @@ lose:
}
It is unclear whether these changes will be included in dash 0.5.6.1
on Ubuntu.
For now the only way to make the command:
$ sh -c 'echo 1 >fсf.dash' && ls *.dash | od -c | grep 201
to work is to reconfigure sh
back to bash
:
$ sudo dpkg-reconfigure dash
Are there other alternatives?
Of the several shells (or versions) I tried, only Dash and Busybox Ash failed.
$ for sh in bash2.05b bash3.2 bash4.0 bash4.1 bash4.2 dash zsh ksh pdksh mksh ash; do $sh -c 'locale > с.$0'; done
$ csh -c 'locale > с.csh'
$ fish -c 'locale > с.fish'
$ ls -1
?.ash
?.dash
с.bash2.05b
с.bash3.2
с.bash4.0
с.bash4.1
с.bash4.2
с.csh
с.fish
с.ksh
с.mksh
с.pdksh
с.zsh
The contents were all the same.
From man dash
:
Only features designated by POSIX, plus a few Berkeley extensions, are being incorporated into this shell. This man page is not intended to be a tutorial or a complete specification of the shell.
POSIX says:
The POSIX locale contains the characters in Portable Character Set , which have the properties listed in LC_CTYPE . In other locales, the presence, meaning, and representation of any additional characters are locale-specific.
and
Wide-character codes for other characters are locale and implementation-defined. ... POSIX.1-2008 provides no means of defining a wide-character codeset.
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