How to find and replace string without use command Sed?

The classic alternative for single letter substitutions is the tr command which should be available on just about any system:

$ echo "foobar" | tr a b   
foobbr

tr is better than sed for this actually since using sed (let alone perl or awk) for single letter substitutions is like using a sledge hammer to kill a fly.

grep is not designed for this, it does not modify its input, it only searches through it.

Alternatively, you can use the shell's substitution capabilities:

$ foo="foobar"
$ echo ${foo//a/b}
foobbr

We could give you more specific answers if you explained exactly what problem you are trying to solve.

Yes there are a variety of ways to do this. You can use awk, perl, or bash to do these activities as well. In general though sed is probably the most apropos tool for doing these types of tasks.

Examples

Say I have this sample data, in a file data.txt:

foo bar 12,300.50
foo bar 2,300.50
abc xyz 1,22,300.50

awk

$ awk '{gsub("foo", "foofoofoo", $0); print}' data.txt 
foofoofoo bar 12,300.50
foofoofoo bar 2,300.50
abc xyz 1,22,300.50

Perl

$ perl -pe "s/foo/foofoofoo/g" data.txt 
foofoofoo bar 12,300.50
foofoofoo bar 2,300.50
abc xyz 1,22,300.50

If you're working with a file rather than a stream, you could use the standard text editor, ed:

printf '%s\n' ',s/a/b/g' w q | ed file.txt

This should be available on any *nix. The comma in ',s/a/b/g' tells ed to work on every line (you can also use %, which will be more familiar if you're used to vim), and the rest of it is a standard search and replace. w tells it to write (save) the file, q tells it to exit.

Note that, unlike sed's -i option (and similar options in other tools), this actually does edit the file in-place rather than cheating with temporary files.

I don't think it's possible to get this working with streams, but then I don't really know much about ed and I wouldn't be surprised if it actually does have that capability (the unix philosophy being what it is).

Using the ancestor ed command :

Just printing on STDOUT :

ed -s file <<!
s/a/b/g
p
q
!

replacing in-place :

ed -s file <<!
s/a/b/g
w
q
!