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How to get specific lines?

 
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# 1  
Old 12-10-2014
How to get specific lines?
Hi all,

I am a beginner to bash shell. I am trying to get multiple lines from file1 using the line numbers listed in file2. For example, file2 looks like:
Code:
1
3
4
8
10
...

How may I get the corresponding lines in file1 please? Any comment will be appreciated.

Many thanks,
sxiong
# 2  
Old 12-10-2014
Try this:
Code:
while read number; do
 sed -n ${number}p file1
done < file2

This User Gave Thanks to junior-helper For This Post:
sxiong
# 3  
Old 12-10-2014
Quote:
Originally Posted by sxiong
Hi all,

I am a beginner to bash shell. I am trying to get multiple lines from file1 using the line numbers listed in file2. For example, file2 looks like:
Code:
1
3
4
8
10
...

How may I get the corresponding lines in file1 please? Any comment will be appreciated.

Many thanks,
sxiong
Simple method might be something like:

Code:
for i in `cat $file2`
do
  head -$i  $file1  | tail -1
done

not sure if there's a cleaner or more efficient way, though Smilie
This User Gave Thanks to Ditto For This Post:
sxiong
# 4  
Old 12-10-2014
Hi

Have you tried while read N;do grep -n ^$N *spec;done<list.txt yet?

hth
This User Gave Thanks to sea For This Post:
sxiong
# 5  
Old 12-10-2014
Try

Code:
sed 's/^/NR==/' linesfile | awk -f - datafile

This User Gave Thanks to senhia83 For This Post:
sxiong
# 6  
Old 12-10-2014
Try:
Code:
awk 'NR==FNR{A[$1]; next} FNR in A' file2 file1

These 2 Users Gave Thanks to Scrutinizer For This Post:
junior-helper sxiong
 
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