 | | From: | Adam Smith | | Subject: | Sed substitution of metacharacters in regex | | Date: | Fri, 07 Jan 2005 07:33:48 -0800 |
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 | Hello,
Replacing a metacharacter with another, (a "|" with a tab "\t" ) in |
delimited fields in a record
Neither ==>
sed 's/\|/\\t/g' pmdat6a.tmp > pmdat6b.tmp
nor
sed 's/\|/\\t/g' pmdat6a.tmp > pmdat6b.tmp
works
Creates "t" delimited fields in record instead
Thanks
-- Adam --
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| | From: | Ed Morton | | Subject: | Re: Sed substitution of metacharacters in regex | | Date: | Fri, 07 Jan 2005 09:34:33 -0600 |
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Adam Smith wrote:
> Hello,
>
> Replacing a metacharacter with another, (a "|" with a tab "\t" ) in |
> delimited fields in a record
>
> Neither ==>
> sed 's/\|/\\t/g' pmdat6a.tmp > pmdat6b.tmp
No need to escape the |, e.g.:
PS1> echo "a|b" | sed 's/|/ /'
a b
PS1> echo "a|b" | sed 's/|/\\t/'
a\tb
Whichever you prefer...
Regards,
Ed.
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| | From: | Adam Smith | | Subject: | Re: Sed substitution of metacharacters in regex | | Date: | Fri, 07 Jan 2005 08:33:26 -0800 |
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| Have I missed something here?
Ed Morton wrote:
>
>
> Adam Smith wrote:
>
>> Hello,
>>
>> Replacing a metacharacter with another, (a "|" with a tab "\t" ) in |
>> delimited fields in a record
>>
>> Neither ==>
>> sed 's/\|/\\t/g' pmdat6a.tmp > pmdat6b.tmp
>
>
> No need to escape the |, e.g.:
>
> PS1> echo "a|b" | sed 's/|/ /'
> a b
> PS1> echo "a|b" | sed 's/|/\\t/'
> a\tb
>
The \t is supposed to be a non-printable character for the tab, and
that's what is needed to be inserted not the "\t"
> Whichever you prefer...
>
> Regards,
>
> Ed.
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| | From: | Stephane CHAZELAS | | Subject: | Re: Sed substitution of metacharacters in regex | | Date: | Fri, 7 Jan 2005 16:59:04 +0000 |
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| 2005-01-07, 08:33(-08), Adam Smith:
[...]
>> PS1> echo "a|b" | sed 's/|/ /'
>> a b
>> PS1> echo "a|b" | sed 's/|/\\t/'
>> a\tb
>>
> The \t is supposed to be a non-printable character for the tab, and
> that's what is needed to be inserted not the "\t"
[...]
On the right hand side of a substitution, \ is only used in \\,
\&, \1, \2..., \n, \/ (extension possibles with some sed
implementations).
The tabulation character may not be printable, it's still a
valid character in an argument to a command.
sed 's/|/ /g'
^^^^^^^
tab character here
is a valid command.
If you have troubles entering a character in your shell,
try .
If your shell supports the $'...' special quotes (ksh93, zsh,
bash), try:
sed $'s/|/\t/g'
But beware "\t" is turned into a character by the shell
before passing the string as an argument to sed.
Alternatively, you can have a variable per control character
this way:
eval "`echo \"SOH='a' STX='b' ETX='c' EOT='d' ENQ='e' ACK='f' \
BEL='g' BS='h' HT='i' LF='j' VT='k' FF='l' CR='m' SO='n' \
SI='o' DLE='p' DC1='q' DC2='r' DC3='s' DC4='t' NAK='u' \
SYN='v' ETB='w' CAN='x' EM='y' SUB='z' ESC='{' FS='|' GS='}' \
RS='~' US='@'\" | tr '[a-}]@' '[\1-\36]\37'`"
Now you can do:
sed "s/|/$HT/g"
(again, $HT is expanded by the shell, it's a real tab character
in the argument sed gets from the shell).
--
Stephane
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| | From: | Ed Morton | | Subject: | Re: Sed substitution of metacharacters in regex | | Date: | Fri, 07 Jan 2005 10:35:33 -0600 |
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Adam Smith wrote:
> Have I missed something here?
Seems like it. See below.
> Ed Morton wrote:
>> PS1> echo "a|b" | sed 's/|/ /'
>> a b
>> PS1> echo "a|b" | sed 's/|/\\t/'
>> a\tb
>>
> The \t is supposed to be a non-printable character for the tab, and
> that's what is needed to be inserted not the "\t"
Then use the first version, i.e. just insert a tab character in your sed
command.
Ed.
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| | From: | Laurenz Albe | | Subject: | Re: Sed substitution of metacharacters in regex | | Date: | Fri, 7 Jan 2005 15:43:11 +0000 (UTC) |
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| In comp.unix.shell Adam Smith wrote:
> Replacing a metacharacter with another, (a "|" with a tab "\t" ) in |
> delimited fields in a record
>
> Neither ==>
> sed 's/\|/\\t/g' pmdat6a.tmp > pmdat6b.tmp
>
> nor
>
> sed 's/\|/\\t/g' pmdat6a.tmp > pmdat6b.tmp
>
> works
> Creates "t" delimited fields in record instead
Instead of writing \\t, insert a tab character to produce something like
sed -e 's/|/ /g'
Sometimes hitting the tab key is enough, on some shells typing
Ctrl+V and then hitting the tab key works.
Yours,
Laurenz Albe
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| | From: | Adam Smith | | Subject: | Re: Sed substitution of metacharacters in regex | | Date: | Fri, 07 Jan 2005 08:36:16 -0800 |
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| Except that the code is embedded in script being run by the cron daemon,
no keyboard intervention !!!!
Laurenz Albe wrote:
> In comp.unix.shell Adam Smith wrote:
>
>>Replacing a metacharacter with another, (a "|" with a tab "\t" ) in |
>>delimited fields in a record
>>
>>Neither ==>
>>sed 's/\|/\\t/g' pmdat6a.tmp > pmdat6b.tmp
>>
>>nor
>>
>>sed 's/\|/\\t/g' pmdat6a.tmp > pmdat6b.tmp
>>
>>works
>>Creates "t" delimited fields in record instead
>
>
> Instead of writing \\t, insert a tab character to produce something like
>
> sed -e 's/|/ /g'
>
> Sometimes hitting the tab key is enough, on some shells typing
> Ctrl+V and then hitting the tab key works.
>
> Yours,
> Laurenz Albe
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| | From: | Ed Morton | | Subject: | Re: Sed substitution of metacharacters in regex | | Date: | Fri, 07 Jan 2005 10:37:37 -0600 |
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Adam Smith wrote:
> Except that the code is embedded in script being run by the cron daemon,
> no keyboard intervention !!!!
No-one's suggesting keyboard intervention, just edit the script that
cron is running to use a tab character in the sed command (see below if
you're not sure how to do that). And please don't top-post
(http://en.wikipedia.org/wiki/Top-posting).
Ed.
> Laurenz Albe wrote:
>> Instead of writing \\t, insert a tab character to produce something like
>>
>> sed -e 's/|/ /g'
>>
>> Sometimes hitting the tab key is enough, on some shells typing
>> Ctrl+V and then hitting the tab key works.
>>
>> Yours,
>> Laurenz Albe
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| | From: | Adam Smith | | Subject: | Re: Sed substitution of metacharacters in regex | | Date: | Fri, 07 Jan 2005 09:16:03 -0800 |
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Ed Morton wrote:
>
>
> Adam Smith wrote:
>
>> Except that the code is embedded in script being run by the cron
>> daemon, no keyboard intervention !!!!
>
>
> No-one's suggesting keyboard intervention, just edit the script that
> cron is running to use a tab character in the sed command (see below if
> you're not sure how to do that). And please don't top-post
> (http://en.wikipedia.org/wiki/Top-posting).
>
> Ed.
>
>> Laurenz Albe wrote:
>
>
>
>>> Instead of writing \\t, insert a tab character to produce something like
>>>
>>> sed -e 's/|/ /g'
>>>
>>> Sometimes hitting the tab key is enough, on some shells typing
>>> Ctrl+V and then hitting the tab key works.
>>>
I'll be darn'd, never knew this - the Ctrl+V worked
thanks
>>> Yours,
>>> Laurenz Albe
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| | From: | Adam Smith | | Subject: | Re: Sed substitution of metacharacters in regex | | Date: | Fri, 07 Jan 2005 11:56:00 -0800 |
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Ed Morton wrote:
>
>
> Adam Smith wrote:
>
>> Except that the code is embedded in script being run by the cron
>> daemon, no keyboard intervention !!!!
>
>
> No-one's suggesting keyboard intervention, just edit the script that
> cron is running to use a tab character in the sed command (see below if
> you're not sure how to do that). And please don't top-post
> (http://en.wikipedia.org/wiki/Top-posting).
>
> Ed.
>
>> Laurenz Albe wrote:
>
>
>
>>> Instead of writing \\t, insert a tab character to produce something like
>>>
>>> sed -e 's/|/ /g'
>>>
>>> Sometimes hitting the tab key is enough, on some shells typing
>>> Ctrl+V and then hitting the tab key works.
>>>
In prior post I expressed surprise that this worked, but alas it was
illusory
All it did was to insert the number of 'white spaces' equivalent to one
tab mark
>>> Yours,
>>> Laurenz Albe
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