Question

我基本上想这样做:

cat file | grep  <expression>  | sed  s/<expression>/<replacement>/g

不必写两字:

cat file | sed  s/<expression>/<replacement>/g

难道有办法告诉不要印刷不符合替代指挥部常规表述的线吗?

Answer 1

你的档案载有你想要替代的文本。

$ cat new.text 
A
B

If you want to change A to a then ideally we do the following -

$ sed  s/A/a/  new.text 
a
B

But if you don t wish to get lines that are not affected with the substitution then you can use the combination of n and p like follows -

$ sed -n  s/A/a/p  new.text 
a

Answer 2

这或许有助于你:

sed  /<expression>/!d;s//<replacement>/g  file

Or

sed  s/<expression>/<replacement>/gp;d  file

Answer 3

cat file | sed -n  /<expression>/{s//<replacement>/g;p;}