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Old 04-10-2006, 09:27 PM   #1
tomolesonjr
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Question how to save output from a command to a variable?


I have a readline script. I want to use its output which by name is one line of a text file. how do I or even can I save this to a variable in a script file?

Thanks,
Tom
 
Old 04-10-2006, 10:32 PM   #2
tomolesonjr
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I got it. play around long enough.

sh readline myfile 41 will read line 41. I'm doing a ls > myfile.

so, grep if `sh readline myfile 41` works.

the ` was the trick.

the goal is to do an ls * > myfile. from any directory. anyhow.
 
Old 04-10-2006, 11:38 PM   #3
pixellany
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Backtick--yes--good thing
Absolute best newbie---finds out answer before lumbering graybeards get around to it.
 
Old 04-11-2006, 08:10 AM   #4
Hobbletoe
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An alternative to backticks in bash is $(cmd). I generally use backticks myself, but our work servers use and older version of bash, and I came across something that didn't work with backticks, but did with the $().
 
Old 04-13-2006, 04:48 PM   #5
tomolesonjr
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yes, are nested backticks acceptable?

for instance...

n=`add $2 1`
then compare `sh readline $1 $2` and `sh readline $1 $n` is that where I might use $()?

readline is a head -nM and then a tail -n1 to get the Mth line. the file is a listing of files, no repeats. so this comparison is sort of like an end of file.

-Tom
 
Old 04-17-2006, 04:32 PM   #6
tomolesonjr
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the finished product: th

lastline:
n=`sh add $2 1`
test `sh readline $1 $2` = `sh readline $1 $n`

readline:
# $1 filename
# $2 line number

head -n$2 $1 > temp1
tail -n1 temp1

grep*:

# $1 list of directories to start search
# $2 search pattern for grep


n=1

while ! `sh lastline $1 $n`
do
mydir=`sh readline $1 $n`
find $mydir -type f > filelistings
n=`sh add $n 1`
m=1
while ! `sh lastline filelistings $m`
do
myfile=`sh readline filelistings $m`
m=`sh add $m 1`
grep -H $2 $myfile
done
myfile=`sh readline filelistings $m`
grep -H $2 $myfile
done
# still have one directory to search!
mydir=`sh readline $1 $n`
m=1

find $mydir -type f > filelistings
while ! `sh lastline filelistings $m`
do
myfile=`sh readline filelistings $m`
m=`sh add $m 1`
grep -H $2 $myfile
done
myfile=`sh readline filelistings $m`
grep -H $2 $myfile
done
 
Old 04-19-2006, 04:04 PM   #7
tomolesonjr
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this isn't homework, but it's hawkeye college, in waterloo, IA
 
  


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