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How to delete all lines with less then 32 characters from a textfile?

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Top Forums Shell Programming and Scripting How to delete all lines with less then 32 characters from a textfile?
# 1  
Old 02-25-2010
How to delete all lines with less then 32 characters from a textfile?
I need to delete all lines with less then 32 characters from a textfile. Smilie
# 2  
Old 02-25-2010
Code:
perl -nl -i.bak -e 'print if length > 32' yourfile

It will save the original file as a copy with the extension .bak
# 3  
Old 02-25-2010
What if Clint Eastwood was a UNIX sysadmin?

Quote:
Originally Posted by Harry Callahan
I know what you're thinking. "Does the unlink(2) syscall reclaim all resources associated with a file even if a process has the file open?" Well, to tell you the truth, in all this excitement I kind of lost track myself. But being as this is a .44 rm, the most powerful unix userland executable in the world, and would blow your file clean off, you've got to ask yourself one question: Do I feel lucky? Well, do ya, punk?
Code:
(rm data; sed '/.\{32\}/!d' > data) < data

To be clear, even if this works fine for you, it is a dangerous way of doing business. A power failure at just the right moment could leave you with no directory link to your data.

A safe, non-Dirty Harry approved version:
Code:
mv data data.bak; sed '/.\{32\}/!d' < data.bak > data

Last edited by alister; 02-25-2010 at 12:15 PM..
# 4  
Old 02-25-2010
Awk and shell version.
Code:
awk 'length($0) >=32 { print } '  infile > outfile

Code:
#!/someposixshell
while read line 
do
      [ ${#line} -lt 32 ] && continue
      echo $line
done < infile > outfile

# 5  
Old 02-25-2010
Hi, kshji

At the cost of readability for AWK newbies, you can minimized that to:
Code:
awk 'length()>31' infile > outfile

And the shell version to:
Code:
#!/someposixshell
while IFS="" read -r line 
do
      [ ${#line} -gt 31 ] && echo "$line"
done < infile > outfile

It is necessary to disable IFS field splitting to prevent losing leading/trailing whitespace. The -r raw option is required to prevent joining lines that end in backslash with the line that follows. And the $line argument to echo needs to be quoted to prevent the replacing of runs of IFS whitespace with a single space.

Cheers,
Alister
Last edited by alister; 02-25-2010 at 12:40 PM..
# 6  
Old 02-25-2010
Quote:
Originally Posted by alister
Hi, kshji

At the cost of readability for AWK newbies, you can minimized that to:
Code:
awk 'length()>31' infile > outfile

And the shell version to:
Code:
#!/someposixshell
while IFS="" read -r line 
do
      [ ${#line} -gt 31 ] && echo "$line"
done < infile > outfile

It is necessary to disable IFS field splitting to prevent losing leading/trailing whitespace. The -r raw option is required to prevent joining lines that end in backslash with the line that follows. And the $line argument to echo needs to be quoted to prevent the replacing of runs of IFS whitespace with a single space.

Cheers,
Alister
Code:
awk 'length>31' infile > outfile

Smilie
# 7  
Old 02-25-2010
My AWK version

Code:
'/.{32,}/'
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