J
Justin To
Hi, how do I delete a line in a file and remove the empty space
afterward?
Thanks!
afterward?
Thanks!
M
Marc Heiler
There are many ways to solve this.
One I use often (which is not very elegant but rather easy) is to use
File.readlines on your file, find the line in that array to kill it, and
save the array to a file finally again.
BTW what do you mean with "empty space"? I guess it will be easy if you
make a small file as example
One I use often (which is not very elegant but rather easy) is to use
File.readlines on your file, find the line in that array to kill it, and
save the array to a file finally again.
BTW what do you mean with "empty space"? I guess it will be easy if you
make a small file as example
J
Justin To
BTW what do you mean with "empty space"? I guess it will be easy if you
File:
a
b
c
d
program: delete(b)
File:
a
<-- empty space
c
d
should be...
File:
a
c
d
Thanks!
make a small file as example
File:
a
b
c
d
program: delete(b)
File:
a
<-- empty space
c
d
should be...
File:
a
c
d
Thanks!
M
Marc Heiler
This should get you started. There are probably 1000 ways but well,
someone else can do that
The test_file had this content:
a
b
c
d
The new_file has
a
b
d
class DeleteLine
def initialize(read_this_file = 'test_file')
@file = File.readlines(read_this_file)
delete_line 3
save_to
end
def delete_line(which_line = 1)
@file.delete_at(which_line-1) # we may count first line as 1, second
line as 2 etc.. otherwise remove the -1 part
end
def save_to(this_file = 'new_file')
File.open(this_file, 'w+') {|f| f.write @file.join() }
end
end
DeleteLine.new
someone else can do that
The test_file had this content:
a
b
c
d
The new_file has
a
b
d
class DeleteLine
def initialize(read_this_file = 'test_file')
@file = File.readlines(read_this_file)
delete_line 3
save_to
end
def delete_line(which_line = 1)
@file.delete_at(which_line-1) # we may count first line as 1, second
line as 2 etc.. otherwise remove the -1 part
end
def save_to(this_file = 'new_file')
File.open(this_file, 'w+') {|f| f.write @file.join() }
end
end
DeleteLine.new
R
Reid Thompson
grep -v "character string unique to line to be removed" file > tmpfile
mv tmpfile file
J
Jimmy Kofler
Justin said:
Some additional in-place file editing options on Unix:
/bin/ed -s file.txt <<< $'/b/d\nw' # delete first line containing "b"
/bin/ed -s file.txt <<< $'g/b/d\nw' # delete all lines containing "b"
/usr/bin/sed -i "" -e '/b/d' file.txt
/bin/ed -s file.txt <<< $'2,2d\nw' # delete second line
/usr/bin/sed -i "" -e '2,2d' file.txt
More on the ed text editor here:
http://bash-hackers.org/wiki/doku.php?id=howto:edit-ed
Using Ruby from the command line:
ruby -p -i -e 'm ||= 0; m == 1 ? $_ : $_.sub!(/^.*2.*$/m, "") || $_; m =
1 unless $~.nil?' file.txt
ruby -p -i -e '$_.sub!(/^.*b.*$/m, "")' file.txt
ruby -p -i -e '$_.sub!(/^.*$/m, "") if $. == 2' file.txt
For more information on selective deletion of certain lines see:
http://www.fepus.net/ruby1line.txt
Cheers,
j.k.