How can I delete everything after a word from multiple line in a file

Question

In the following file:

semi1245  5465 and taxes ?>:"  foo 214 sdnfv 1>?<: Wed
dsfsdf  46 and gsdgsd blah and blah taxes   foo 214 sdnfv 1>?<: Wed sadfaads

I want to delete everything after foo (including foo) from every lines (If the line contains foo) .

My desired output:

semi1245  5465 and taxes ?>:" 
dsfsdf  46 and gsdgsd blah and blah taxes 

Answer 1

sed -i.bak 's/foo.*//' testfile.txt will be sufficient for this.

-i.bak edits your file in-place, and keeps a copy of your original file with the extension filename.bak.

's/foo.*//' is the substitution part. 'foo.*' identifies 'foo' followed by any number of characters up to the end of the line. We catch this pattern and replace it with an empty string, effectively removing it.

Answer 2

Here are a couple of alternatives:: using GNU grep with the perl mode enabled.

grep -Po '^.*?(?=foo|$)' file

The regex looks for the first match of foo OTW skids till the end of line. The anchoring to the beginning of line ^ prevents grep ping of multiple matches in a line and lookahead prevents the foo from being included in the match output.

Using Posix sed we place a marker \n and print only upto that incase the foo regex matched. OTW the whole line is printed.

sed -ne 's/foo/\n/;P' file

Split the line on foo so that $1 is anything prior to the first foo.

awk -F 'foo' 'NF>1 {$0=$1}1' file