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Just annotations of little "how to's", so I know I can find how to do something I've already done when I need to do it again, in case I don't remember anymore, which is not unlikely. Hopefully they can be useful to others, but I can't guarantee that it will work, or that it won't even make things worse.
Old

Give a default/non-null value in order to avoid the "unary operator expected" error

Posted 02-19-2014 at 03:00 PM by the dsc (linux-related notes)
Tags bash
Quote:
Originally Posted by cfajohnson
Quote:
i am trying to compare a value with value 50. but i am getting
"[: -lt: unary operator expected"

I am using

if [ $j -lt 50 ]
then
echo "------------"

fi
Make sure that $j expands to a value. Best is to set it explicitly, but you can also give it a default value (0 in this example):


Code:
if [ ${j:-0} -lt 50 ]
http://www.unix.com/302295072-post3.html...
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Posted in Uncategorized
Views 1539 Comments 0 the dsc is offline
Old

"Alpha" of an auto-renaming existing files "mv" script/function/alias

Posted 02-18-2014 at 01:02 PM by the dsc (linux-related notes)
Please don't test this on files you don't care to lose/folders you don't care to mess. I just tested once with an explicit (non-variable/"$2") destination, it seems to have worked. I don't have it as an alias or anything, it was just an "one liner" I came up with.

Code:
for on in "$1" ; do nn=$on ; num=1 ; until [ ! -f "$2/$nn" ] ; do nn="$(echo $nn | sed 's| ([0-9]*)||' | sed "s|\.| ($num).|")" ; num=$((num+1)) ; echo $nn ; done
...
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Posted in Uncategorized
Views 1003 Comments 0 the dsc is offline

  



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