I am new to unix shell.

I need to add a single line to the beginning of multiple ( 100's )
files. Can I automate this through shell scripting and if so, can
anyone point me to a newbie resource.

Thanx Randy

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Randy wrote:
> I am new to unix shell.
>
> I need to add a single line to the beginning of multiple ( 100's )
> files. Can I automate this through shell scripting and if so, can
> anyone point me to a newbie resource.
>
> Thanx Randy
>
for file in *; do echo "chars_to_add${file}"; done
Something like that?
Mabye you use find and some shell scripting depending on your $SHELL.

b.r.,
- --
Stephan 'smg' Grein, <stephan at stephan minus rockt dot de>
http://stephangrein.de
GnuPG-Key-ID: 0xF8C275D4
FingerPrint: 5B6F 134A 189B A24D 342B 0961 8D4B 0230 F8C2 75D4
Geek by nature, Linux by choice.
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On 2006-08-23, Randy wrote:
> I am new to unix shell.
>
> I need to add a single line to the beginning of multiple ( 100's )
> files. Can I automate this through shell scripting and if so, can
> anyone point me to a newbie resource.

line="Inserted line"
for file in ./* ## replace * with whatever pattern you want
do
{
printf "%s\n" "$line"
cat "$file"
} > tempfile && mv tempfile "$file"
done

--
Chris F.A. Johnson, author <http://cfaj.freeshell.org/shell>
Shell Scripting Recipes: A Problem-Solution Approach (2005, Apress)
===== My code in this post, if any, assumes the POSIX locale
===== and is released under the GNU General Public Licence

Randy wrote:
> I am new to unix shell.
>
> I need to add a single line to the beginning of multiple ( 100's )
> files. Can I automate this through shell scripting and if so, can
> anyone point me to a newbie resource.
>
> Thanx Randy
>
with GNU tools use:

for FILE in *
do
echo "$LINE" | cat - "$FILE" > "$FILE.NEW"
mv "$FILE.NEW" "$FILE"
done

or use

find -type f -print0 | xargs -r0 sed -i "0i$LINE"

look for

man 1 bash
echo
for
man 1 cat
man 1 mv
info find
man 1 xargs
info sed

Regards,

Steffen Schuler

On Wed, 23 Aug 2006 21:20:58 +0200, Steffen Schuler wrote:
> Randy wrote:
>> I am new to unix shell.
>>
>> I need to add a single line to the beginning of multiple ( 100's )
>> files. Can I automate this through shell scripting and if so, can
>> anyone point me to a newbie resource.
>>
>> Thanx Randy
>>
> with GNU tools use:
>
> for FILE in *
> do
> echo "$LINE" | cat - "$FILE" > "$FILE.NEW"
> mv "$FILE.NEW" "$FILE"
> done

There's nothing GNU specific above. However, the usage of echo
makes it incorrect, as it depends on how the GNU shell was
compiled. The GNU shell (bash) has printf, as every other POSIX
conformant shell (and there's a printf command as well in the
GNU coreutils), so you shouldn't need to use echo.

> or use
>
> find -type f -print0 | xargs -r0 sed -i "0i$LINE"
[...]

Yes, there the directory ommitted, -print0, -r, -0, -i, 0,
i<text> are all GNU specific and nor POSIX (though some if not
all can also be found in some BSDs).

The Unix/POSIX equivalent would be:

export LINE
find . -type f -exec sh -c '
for f do
{
rm -f "$f" &&
sed "1i\\
$LINE" > "$f"
} < "$f"
done' inline {} +

Except that contrary to with GNU sed, the ownership and
permissions of the files would not be attempted to be restored.

With zsh:

zmodload zsh/mapfile
for f (**/*(.DN)) mapfile[$f]=$LINE$'\n'$mapfile[$f]

--
Stephane

Stephane Chazelas wrote:
> On Wed, 23 Aug 2006 21:20:58 +0200, Steffen Schuler wrote:
> There's nothing GNU specific above. However, the usage of echo
> makes it incorrect, as it depends on how the GNU shell was
> compiled.

Thank you Stephane for this info. I didn't know what you wrote about
echo.

Regards,

Steffen Schuler

2006-08-26, 16:53(+02), Steffen Schuler:
> Stephane Chazelas wrote:
>> On Wed, 23 Aug 2006 21:20:58 +0200, Steffen Schuler wrote:
>> There's nothing GNU specific above. However, the usage of echo
>> makes it incorrect, as it depends on how the GNU shell was
>> compiled.
>
> Thank you Stephane for this info. I didn't know what you wrote about
> echo.
[...]

That's in the FAQ.

echo is one of the least portable commands.

POSIX says that its behavior is unspecified.

UNIX says that it must behave like on System V where no option
is recognised, where \n, \b, \f... are expanded.

bash, by defaults behaves the BSD way. It is almost POSIX
conformant. The only problem being that echo -e doesn't output
"-e<LF>".

However you can compile bash so that its echo is more Unix
conformant (expands the \x), you can achieve the same by issuing
"shopts -s xpg_echo". However, it is still not POSIX nor UNIX as
echo -e doesn't output "-e".

More generally.

echo "$var"

doesn't output the content of $var followed by a newline
character unless $var doesn't start with a - or doesn't contain
any backslash character.

printf is the command that must be used instead of echo.

--
Stéphane