Delete the first known character in a string with sed

Question

How does one delete the first known character in a string with sed?

For example, say I want to delete the first character (which is @) in the string "@ABCDEFG1234"

I want sed to verify whether "@" exists as the first character. If so, it should delete the character.

score 31 · Answer 1 · answered Sep 14 '11 at 06:55

31

There's no need to capture and replace.

sed 's/^@//'

This replaces the character @ when it's first ^ in the string, with nothing. Thus, deleting it.

answered Sep 14 '11 at 06:55

johnny

score 17 · Accepted Answer · answered Jun 27 '10 at 14:39

17

sed 's/^@\(.*\)/\1/'

^ means beginning of the string

@ your known char

(.*) the rest, captured

then captured block will be substituted to output Sorry, can't test it at the moment, but should be something like that

answered Jun 27 '10 at 14:39

Pablo

I want to delete + which does not need to be escaped although it stands for 1 or more in regex. – Timo Nov 04 '20 at 07:56

score 2 · Answer 3 · answered Mar 12 '18 at 03:05

2

You can do this instead.

sed 's/^.//'

^ - Starting character 
. - No of charactes(.. means two characters)

Example :

echo test123 | sed 's/^.//'
est123
echo test123 | sed 's/^..//'
st123

answered Mar 12 '18 at 03:05

2

The question says “I want sed to verify whether "@" exists as the first character. If so, it should delete the character.” Your answer deletes the first character of each line no matter what is it. For example, if a line contains test123, it looks like the OP wants it left alone. – Scott - Слава Україні Mar 12 '18 at 03:57
I like the quick solution of Prakaash, but @Scott you are right when reading the OP carefully. In most of the cases, you do want a distinct character and not any. – Timo Nov 04 '20 at 07:54

3 Answers3