Add/edit line text in file without open editor (linux command)

Question

I know how to add new text to a file, but how can I edit it?

Example: adding hello_world = 1 to test.txt using the following command:

echo "hello_world = 1" >> test.txt

But how can I change 1 to 0 or something else?

What is your mean by without open editor i.e. you don't want use also useful CLI text editor like: vi or nano as well as GUI like: gedit — Pandya, Jul 02 '14 at 12:08
because I want to make a script for my android, I know android use linux kernel and has some linux command. And my script working perfectly — Marco98T, Jul 05 '14 at 09:28

score 35 · Accepted Answer · answered Jul 02 '14 at 11:28

35

Using sed:

sed -i 's/1/0/g' test.txt

In general:

sed -i 's/oldstring/newstring/g' filename

See man sed for more info.

answered Jul 02 '14 at 11:28

Radu Rădeanu

for single substitution, you don't even need a global flag. – Avinash Raj Jul 02 '14 at 11:55
Downvote because answer is already exists here. – c0rp Jul 02 '14 at 12:17
Why do you downvote the correct answer then, cOrp, and not the duplicate question? – foo Sep 03 '20 at 14:19

score 5 · Answer 2 · answered Jul 02 '14 at 11:54

5

Through awk,

awk '{sub(/1/,"0")}1' infile > outfile

Example:

$ echo 'hello_world = 1' | awk '{sub(/1/,"0")}1'
hello_world = 0

answered Jul 02 '14 at 11:54

Avinash Raj

2 Answers2