sed tutorial: sed replace

Sed replace, you can use the sed function: s, replace the text in the file. syntax: ➜ ~ sed 's/regexp/replacement/' file...

mkdir if not exists in linux/unix

mkdir creates a directory if it does not exist, we can use the mkdir -p option. syntax: mkdir -p foo/bar/baz, will create directories foo, foo/bar,...

How to grep ignore case in linux/unix

In linux/unix, we can use the grep -i option to ignore case matching search keywords. grep ignore case syntax: grep -i "keyword" file...