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Good day! Even though you've still got another op in front of you, I know you'll be up and rarin' to go for Brands because anyone that has achieved what you have since your accident, will make sure that it happens kitchen whens the next production?! http://smokeydevo.blogspirit.com/tag/chicken syrup, Very interesting. <<Anchor(faq19)>>
== How can I split a file into line ranges, e.g. lines 1-10, 11-20, 21-30? ==
POSIX specifies the {{{split}}} utility, which can be used for this purpose:

{{{#!highlight bash
split -l 10 input.txt
}}}

For more flexibility you can use {{{sed}}}. The {{{sed}}} command can print e.g. the line number range 1-10:
{{{#!highlight bash
sed 10q # Print lines 1-10 and then quit.
sed '1,5d; 10q' # Print just lines 6-10 by filtering the first 5 then quitting after 10.
}}}

The `d` command stops {{{sed}}} from printing each line. This could alternatively have been done by passing sed the `-n` option and printing lines with the `p` command rather than deleting them with `d`. It makes no difference.

We can now use this to print an arbitrary range of a file (specified by line number):

{{{#!highlight bash
# POSIX shell
file=/etc/passwd
range=10
cur=1
last=$(wc -l < "$file") # count number of lines
chunk=1
while [ $cur -lt $last ]
do
    endofchunk=$(($cur + $range - 1))
    sed -n -e "$cur,${endofchunk}p" -e "${endofchunk}q" "$file" > chunk.$(printf %04d $chunk)
    chunk=$(($chunk + 1))
    cur=$(($cur + $range))
done
}}}

The previous example uses POSIX [[ArithmeticExpression|arithmetic]], which older [[BourneShell|Bourne shells]] do not have. In that case the following example should be used instead:

{{{#!highlight bash
# legacy Bourne shell; assume no printf either
file=/etc/passwd
range=10
cur=1
last=`wc -l < "$file"` # count number of lines
chunk=1
while test $cur -lt $last
do
    endofchunk=`expr $cur + $range - 1`
    sed -n -e "$cur,${endofchunk}p" -e "${endofchunk}q" "$file" > chunk.$chunk
    chunk=`expr $chunk + 1`
    cur=`expr $cur + $range`
done
}}}

Awk can also be used to produce a more or less equivalent result:

{{{#!highlight bash
awk -v range=10 '{print > FILENAME "." (int((NR -1)/ range)+1)}' file
}}}

----
CategoryShell

How can I split a file into line ranges, e.g. lines 1-10, 11-20, 21-30?

POSIX specifies the split utility, which can be used for this purpose:

   1 split -l 10 input.txt

For more flexibility you can use sed. The sed command can print e.g. the line number range 1-10:

   1 sed 10q         # Print lines 1-10 and then quit.
   2 sed '1,5d; 10q' # Print just lines 6-10 by filtering the first 5 then quitting after 10.

The d command stops sed from printing each line. This could alternatively have been done by passing sed the -n option and printing lines with the p command rather than deleting them with d. It makes no difference.

We can now use this to print an arbitrary range of a file (specified by line number):

   1 # POSIX shell
   2 file=/etc/passwd
   3 range=10
   4 cur=1
   5 last=$(wc -l < "$file") # count number of lines
   6 chunk=1
   7 while [ $cur -lt $last ]
   8 do
   9     endofchunk=$(($cur + $range - 1))
  10     sed -n -e "$cur,${endofchunk}p" -e "${endofchunk}q" "$file" > chunk.$(printf %04d $chunk)
  11     chunk=$(($chunk + 1))
  12     cur=$(($cur + $range))
  13 done

The previous example uses POSIX arithmetic, which older Bourne shells do not have. In that case the following example should be used instead:

   1 # legacy Bourne shell; assume no printf either
   2 file=/etc/passwd
   3 range=10
   4 cur=1
   5 last=`wc -l < "$file"` # count number of lines
   6 chunk=1
   7 while test $cur -lt $last
   8 do
   9     endofchunk=`expr $cur + $range - 1`
  10     sed -n -e "$cur,${endofchunk}p" -e "${endofchunk}q" "$file" > chunk.$chunk
  11     chunk=`expr $chunk + 1`
  12     cur=`expr $cur + $range`
  13 done

Awk can also be used to produce a more or less equivalent result:

   1 awk -v range=10 '{print > FILENAME "." (int((NR -1)/ range)+1)}' file


CategoryShell

BashFAQ/019 (last edited 2022-04-19 12:13:19 by emanuele6)