Finding and replacing lines that begin with a pattern
21,321
Solution 1
Use a ^
symbol to represent the beginning of a line:
sed -i 's/^a\tb.*$/REPLACED TEXT/g' file.TXT
Exmplanation:
^
means beginning of line/input\t
means tab symbol.
means any character*
means zero or more of the preceeding expression$
means end of line/input
Solution 2
The following will replace the entire line if it begins with a<tab>b<tab>c
. The .*$
makes the match include the entire line for replacement. Your example regex included c
but the prose only mentioned a
and b
, so it wasn't quite clear if c
is required. If not, then remove \tc
from the regex.
s/^a\tb\tc.*$/REPLACED TEXT/g
Solution 3
With awk
awk '/^a\tb/{$0="REPLACED TEXT"} 1' foo.txt
Author by
Ank
Updated on July 30, 2022Comments
-
Ank over 1 year
I have a text in a file file.txt like this
xxxxxxxxxxxxxxx xxxxxxxxxxxxxxx a b c // delimited by tab xxxxxxxxxxxxxxx xxxxxxxxxxxxxxx
I know using
sed
I can find and replace text in a file. If a line starts with a b(seperated by a tab) I need to replace it with d e f. So the above file will bexxxxxxxxxxxxxxx xxxxxxxxxxxxxxx d e f // delimited by tab xxxxxxxxxxxxxxx xxxxxxxxxxxxxxx
I can do this to find and replace, I want only those instances where the line starts with a b and replace the whole line.
sed -i 's/a/\t/\b/\t\/c/REPLACED TEXT/g' file.TXT