How to replace specific line positions in sed

sed

I need to be able to use sed (or anything else) to replace a specific line position, I'm Googleing and can't find anything (yet).

* UPDATE *

this is what I came up so far..

sed 's|\(^.\{67\}\).\{1\}||g' $$

yet this deletes everything from beginning to position 67+1, I want ONLY position 67+1 to be gone..

Best Answer

I first believed youd need this. This will match 66 characters \(.\{66\}\) and store it in \1, put the next two \(.\{2\}\) in \2, and everything else \(.*\) in \3 it will substitute \1\2\3 with \1\3, disappearing you 2 characters you dont want.

sed 's/^\(.\{66\}\)\(.\{2\}\)\(.*\)/\1\3/'

And then I remembered this. This will substitute 2 characters '..' for '' at character 67.

sed 's/..//67'

Related Solutions

Shell Scripting – How to Rename Multiple Files by Replacing Word in File Name

rename 's/ACDC/AC-DC/' *.xxx

from man rename

DESCRIPTION
       "rename" renames the filenames supplied according to the rule specified as the 
first argument.  The perlexpr argument is a Perl expression which is expected to modify the 
$_ string in Perl for at least some of the filenames specified.  If a given filename is not 
modified by the expression, it will not be renamed.  If no filenames are given on
           the command line, filenames will be read via standard input.

For example, to rename all files matching "*.bak" to strip the extension, you might say

rename 's/\.bak$//' *.bak

To translate uppercase names to lower, you'd use

rename 'y/A-Z/a-z/' *

Using sed to prepend zero to four-digit numbers

You wish to prepend to only four-digit numbers, so you need to match beginning and ending, like this:

sed 's/^[0-9]\{4\}$/0&/'

I sometimes use something like this:

sed -r \
    -e 's/^[0-9]{1}$/0&/' \
    -e 's/^[0-9]{2}$/0&/' \
    -e 's/^[0-9]{3}$/0&/' \
    -e 's/^[0-9]{4}$/0&/' \
    -e 's/^[0-9]{5}$/0&/' \
    -e 's/^[0-9]{6}$/0&/'

which should leave all numbers as seven digits. There are of course easier ways with other tools than sed.

Best Answer

Related Solutions

Shell Scripting – How to Rename Multiple Files by Replacing Word in File Name

Using sed to prepend zero to four-digit numbers

Related Topic