Linux remove text from file

Question

I want to write a command with removes an item from a file .todolist like that:

path="$HOME/.todolist"
if [ "$task" == "- " ];
then 
    exit 1
fi 
cat $path | grep -v $1 > $path

When I cat $path | grep -v $1 all works perfect but when I try writing back to the file it leaves the file empty. What am I doing wrong?

Path `path="$HOME/.todolist"` is wrong. change it like `path="$HOME/todolist"` — Grijesh Chauhan, Feb 25 '13 at 17:01
possible duplicate of [Bash: Is it ok to use same input file as output of a piped command?](http://stackoverflow.com/questions/3055005/bash-is-it-ok-to-use-same-input-file-as-output-of-a-piped-command) — Chris Seymour, Feb 25 '13 at 17:18
Besides being ask a gazillion times.. You are clobbing your file, you shouldn't use `path` as a variable name and unless use of `cat`. — Chris Seymour, Feb 25 '13 at 17:33

score 1 · Answer 1 · edited Feb 25 '13 at 17:31

1

As simple as that-

path="$HOME/.todolist"
grep -v $1 $path | sponge $path

edited Feb 25 '13 at 17:31

Chris Seymour

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answered Feb 25 '13 at 17:25

Ben

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score 1 · Answer 2 · answered Feb 25 '13 at 22:06

This may be simpler:

sed -ie "/$1/d" $path

That will delete any line in the file containing the value in $1. The -i option tells sed to edit the file in place (not really, but it works as if it did). If $1 contains /s you'll get an error, though, but you can use other delimiters if you need to:

sed -ie "\%$1%d" $path

Note that with an alternate delimiter you must escape the first one with "\".

score 0 · Answer 3 · answered Feb 26 '13 at 02:04

0

path="$HOME/.todolist"
if [ "$task" == "- " ];
then 
    exit 1
fi 
a=$1
export a

perl -pi -e 'undef $_ if(/$ENV{a}/)' $path

answered Feb 26 '13 at 02:04

Vijay

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Linux remove text from file

3 Answers3