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grep variable with tricky content

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# 1  
Old 12-08-2011
grep variable with tricky content
Hello,
i have this issue:
Code:
text="-8x7YTVNk2KiuY-PWG5zzzjB-zzw"
string=-8x7YTVNk2KiuY-PWG5zzzjB-zzw
echo $text | grep -v \'$string\'
-8x7YTVNk2KiuY-PWG5zzzjB-zzw
echo \'$string\'
'-8x7YTVNk2KiuY-PWG5zzzjB-zzw'

..and ofcourse if I do like this :
Code:
echo $text | grep -v $string
grep: invalid option -- Y
Usage: grep [OPTION]... PATTERN [FILE]...


all this because variable string stores content that begins with "-"

Any ideas how can I grep some text with a variable with such content ?


Moderator's Comments:
Mod Comment How to use code tags
Last edited by Franklin52; 12-08-2011 at 05:53 AM.. Reason: Please use code tags for code and data samples, thank you
# 2  
Old 12-08-2011
use

Code:
 
grep --  -v $string

# 3  
Old 12-08-2011
I'm not familiar with this grep usage, I probably miss something, your command executed as you posted :
Code:
grep --  -v $string
grep: -8x7YTVNk2KiuY-PWG5zzzjB-zzw: No such file or directory

gives me this error. My problem is that the variable $string has content that begins with "-" . the variable $text can very well be a file with lot of content. my problem is variable $string


Moderator's Comments:
Mod Comment Please use code tags!
Last edited by zaxxon; 12-08-2011 at 06:17 AM.. Reason: code tags, see PM
# 4  
Old 12-08-2011
where is your echo statement ?

can you post the $string and $text values ?

---------- Post updated at 03:47 PM ---------- Previous update was at 03:45 PM ----------

Code:
 
$ echo "ab-cd-ef" | grep -v -- $a 
ab-cd-ef

$ echo $a
-ab

---------- Post updated at 03:47 PM ---------- Previous update was at 03:47 PM ----------

Code:
 
$ echo "ab-cd-ef" | grep -v -- $a 
ab-cd-ef

$ echo $a
-ab

This User Gave Thanks to itkamaraj For This Post:
black_fender
# 5  
Old 12-08-2011
Can't you escape the "-" before executing "grep"?

Check below:
Code:
$ text="-8x7YTVNk2KiuY-PWG5zzzjB-zzw"
$ string="-8x7YTVNk2KiuY-PWG5zzzjB-zzw"
$ echo "${text}" | sed 's/^-/\\-/g'
\-8x7YTVNk2KiuY-PWG5zzzjB-zzw

$ nstring=$(echo "${text}" | sed 's/^-/\\-/g')
$ echo "${text}" | grep -cv "${nstring}"
0
$ echo "${text}" | grep -v "${nstring}"

#
# Or, as commented above:
#
$ echo "${text}" | grep -cv -- "${string}"
0
$ echo "${text}" | grep -v -- "${string}"

I hope it helps! =o)
This User Gave Thanks to felipe.vinturin For This Post:
black_fender
# 6  
Old 12-08-2011
Code:
echo $text | grep -- -v $string
grep: -8x7YTVNk2KiuY-PWG5zzzjB-zzw: No such file or directory

obviously I've tried that also. the problem was the parameter order that you provided first. grep -- -v instead of grep -v --

nevertheless it finally worked :

Code:
echo $text | grep -- $string
-8x7YTVNk2KiuY-PWG5zzzjB-zzw

Thank you very much.
Last edited by Franklin52; 12-08-2011 at 06:39 AM.. Reason: Please use code tags for code and data samples, thank you
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