'grep'-line_word_get.md

grep - get line / word

Get a word by characters

grep -o 'key3[^ ]*' <<<'key1="value1" key2="value2" key3="value3" key4="value4"'
# key3="value3"

Get value by key from string multiline or file

grep -Po 'key3=\K[^ ]+' <<<'key1=value1 key2=value2 key3=value3 key4=value4'
# value3

key3= : key
\K : discard matched part
[^ ]+ : get value (limit with next space)

Get line

grep "text to find" file.ext
# text to find

Get line number

grep -n "text to find" file.ext | cut -f1 -d:
# line number

Remove blank lines

# empty lines + lines with spaces
grep -v '^\s*$' file.ext

# empty lines only
grep .