Is there any bash commands to repeat a string, i.e. I want to output
60 '#' (just an example, need to repeat an arbitrary string anyway) in
a single line, say

echo " ##################...[cut]...##"

which is awkward, is there any fast way to achieve this??

many thanks,
lihao

On Sun, 30 Dec 2007 23:48:44 -0800, lihao0129@gmail.com wrote:

> Is there any bash commands to repeat a string, i.e. I want to output 60
> '#' (just an example, need to repeat an arbitrary string anyway) in a
> single line, say
>
> echo " ##################...[cut]...##"
>
> which is awkward, is there any fast way to achieve this??
>
> many thanks,
> lihao

If you are in emacs mode, then typing the following sequence of characters

e c h o space " space esc 6 esc 0 # "

will do what you ask for for a single character. You can set up a macro
that inserts a string and repeat that for the arbitrary string case.

Control-X ( a b c Control-X ) esc 1 esc 9 control-X control-E

to insert 20 copies of "abc".

Or you could write a loop.
Or you use your favorite editor and its facilities to repeat things and
write the command in a script file.

On 2007-12-31, lihao0129@gmail.com wrote:
>
> Is there any bash commands to repeat a string, i.e. I want to output
> 60 '#' (just an example, need to repeat an arbitrary string anyway) in
> a single line, say
>
> echo " ##################...[cut]...##"
>
> which is awkward, is there any fast way to achieve this??

printf -v rept "%60s" ' ' # Older versions: rept=$( printf "%60s" ' ' )
rept=${rept//?/#}


Or:

rept=#
while [ ${#rept} -lt 60 ]
do
rept=$rept$rept$rept
done
repr=${rept:0:60}


Or, for any POSIX shell:

rept=#
while [ ${#rept} -lt 60 ]
do
rept=$rept$rept$rept
done
while [ ${#rept} -gt 60 ]
do
rept=${rept#?}
done


Or:

printf "%60s\n" " " | tr ' ' '#'


Or.....

--
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

Icarus Sparry wrote:
> On Sun, 30 Dec 2007 23:48:44 -0800, lihao0129@gmail.com wrote:
>
>
>>Is there any bash commands to repeat a string, i.e. I want to output 60
>>'#' (just an example, need to repeat an arbitrary string anyway) in a
>>single line, say
>>
>> echo " ##################...[cut]...##"
>>
>>which is awkward, is there any fast way to achieve this??
>>
>>many thanks,
>>lihao
>
>
> If you are in emacs mode, then typing the following sequence of characters
>
> e c h o space " space esc 6 esc 0 # "

Hmm.. - in vi/vim and kornshell's vi mode it would be...

e c h o space " space " esc 6 0 i # esc

....but bash seems not to support that. (Just wondering.)

>
> will do what you ask for for a single character. You can set up a macro
> that inserts a string and repeat that for the arbitrary string case.
>
> Control-X ( a b c Control-X ) esc 1 esc 9 control-X control-E
>
> to insert 20 copies of "abc".
>
> Or you could write a loop.
> Or you use your favorite editor and its facilities to repeat things and
> write the command in a script file.

I suppose the OP wants some terse script expression like echo "#"{60}
(similar to perl's 'x 60') which doesn't seem to be supported in bash.

So I'd resort to s=$( printf "%60s" ); echo " ${s// /#}"

Janis

Hi, thanks both for your hints:- )

On Dec 31, 3:53am, "Chris F.A. Johnson" <cfajohn...@gmail.com> wrote:
> On 2007-12-31, lihao0...@gmail.com wrote:
>
> > Is there any bash commands to repeat a string, i.e. I want to output
> > 60 '#' (just an example, need to repeat an arbitrary string anyway) in
> > a single line, say
>
> > echo " ##################...[cut]...##"
>
> > which is awkward, is there any fast way to achieve this??
>
> printf -v rept "%60s" ' ' # Older versions: rept=$( printf "%60s" ' ' )
> rept=${rept//?/#}
>
> Or:

Very nice, I finally came up with a solution like:

A=$(seq 60)
B=${A//??/#}

works pretty well. :-)

lihao

> rept=#
> while [ ${#rept} -lt 60 ]
> do
> rept=$rept$rept$rept
> done
> repr=${rept:0:60}
>
> Or, for any POSIX shell:
>
> rept=#
> while [ ${#rept} -lt 60 ]
> do
> rept=$rept$rept$rept
> done
> while [ ${#rept} -gt 60 ]
> do
> rept=${rept#?}
> done
>
> Or:
>
> printf "%60s\n" " " | tr ' ' '#'
>
> Or.....
>
> --
> 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

lihao0129@gmail.com wrote:
> Hi, thanks both for your hints:- )
>
> On Dec 31, 3:53 am, "Chris F.A. Johnson" <cfajohn...@gmail.com> wrote:
>
>>On 2007-12-31, lihao0...@gmail.com wrote:
>>
>>
>>>Is there any bash commands to repeat a string, i.e. I want to output
>>>60 '#' (just an example, need to repeat an arbitrary string anyway) in
>>>a single line, say
>>
>>> echo " ##################...[cut]...##"
>>
>>>which is awkward, is there any fast way to achieve this??
>>
>>printf -v rept "%60s" ' ' # Older versions: rept=$( printf "%60s" ' ' )
>>rept=${rept//?/#}
>>
>> Or:
>
>
> Very nice, I finally came up with a solution like:
>
> A=$(seq 60)
> B=${A//??/#}
>
> works pretty well. :-)

But that will not produce a sequence of 60 #'es.
Compare the two outputs...

$ A=$(seq 60) ; B=${A//??/#} ; echo ${#B}
85

$ A=$(printf "%60s") ; B=${A// /#} ; echo ${#B}
60

And your code will produce wrong output depending on the
length of the sequence; try 'seq 61' to see what I mean.

Janis

>
> lihao
>
>
>>rept=#
>>while [ ${#rept} -lt 60 ]
>>do
>> rept=$rept$rept$rept
>>done
>>repr=${rept:0:60}
>>
>> Or, for any POSIX shell:
>>
>>rept=#
>>while [ ${#rept} -lt 60 ]
>>do
>> rept=$rept$rept$rept
>>done
>>while [ ${#rept} -gt 60 ]
>>do
>> rept=${rept#?}
>>done
>>
>> Or:
>>
>>printf "%60s\n" " " | tr ' ' '#'
>>
>> Or.....
>>
>>--
>> 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
>
>
>

On Dec 31, 2:13pm, Janis Papanagnou <Janis_Papanag...@hotmail.com>
wrote:
> Icarus Sparry wrote:
> > On Sun, 30 Dec 2007 23:48:44 -0800, lihao0...@gmail.com wrote:
>
> >>Is there any bash commands to repeat a string, i.e. I want to output 60
> >>'#' (just an example, need to repeat an arbitrary string anyway) in a
> >>single line, say
>
> >> echo " ##################...[cut]...##"
>
> >>which is awkward, is there any fast way to achieve this??
>
> >>many thanks,
> >>lihao
>
> > If you are in emacs mode, then typing the following sequence of characters
>
> > e c h o space " space esc 6 esc 0 # "
>
> Hmm.. - in vi/vim and kornshell's vi mode it would be...
>
> e c h o space " space " esc 6 0 i # esc
>
> ...but bash seems not to support that. (Just wondering.)
>
>
>
> > will do what you ask for for a single character. You can set up a macro
> > that inserts a string and repeat that for the arbitrary string case.
>
> > Control-X ( a b c Control-X ) esc 1 esc 9 control-X control-E
>
> > to insert 20 copies of "abc".
>
> > Or you could write a loop.
> > Or you use your favorite editor and its facilities to repeat things and
> > write the command in a script file.
>
> I suppose the OP wants some terse script expression like echo "#"{60}
> (similar to perl's 'x 60') which doesn't seem to be supported in bash.
>
> So I'd resort to s=$( printf "%60s" ); echo " ${s// /#}"
>

Thanks, you are right, and I want this to show up in my bash
script :- )

"printf" is much better than "seq" I used. :-)

lihao

On Dec 31, 2:37pm, Janis Papanagnou <Janis_Papanag...@hotmail.com>
wrote:
> lihao0...@gmail.com wrote:
> > Hi, thanks both for your hints:- )
>
> > On Dec 31, 3:53 am, "Chris F.A. Johnson" <cfajohn...@gmail.com> wrote:
>
> >>On 2007-12-31, lihao0...@gmail.com wrote:
>
> >>>Is there any bash commands to repeat a string, i.e. I want to output
> >>>60 '#' (just an example, need to repeat an arbitrary string anyway) in
> >>>a single line, say
>
> >>> echo " ##################...[cut]...##"
>
> >>>which is awkward, is there any fast way to achieve this??
>
> >>printf -v rept "%60s" ' ' # Older versions: rept=$( printf "%60s" ' ' )
> >>rept=${rept//?/#}
>
> >> Or:
>
> > Very nice, I finally came up with a solution like:
>
> > A=$(seq 60)
> > B=${A//??/#}
>
> > works pretty well. :-)
>
> But that will not produce a sequence of 60 #'es.
> Compare the two outputs...
>
> $ A=$(seq 60) ; B=${A//??/#} ; echo ${#B}
> 85
>
> $ A=$(printf "%60s") ; B=${A// /#} ; echo ${#B}
> 60
>
> And your code will produce wrong output depending on the
> length of the sequence; try 'seq 61' to see what I mean.
>
> Janis
>

ah, you are right. :-)

lihao