Sed one-liner to delete any line that does not contain lowercase letters

awksed

So, basically

THIS LINE WOULD BE DELETED

and

(THIS LINE WOULD ALSO BE DELETED)

but

Indeed, THIS LINE WOULD NOT

Best Answer

Quite a few ways. Think negatively:

sed '/[a-z]/!d'    # !x runs x if the pattern doesn't match
grep -v '[a-z]'    # -v means print if the regexp doesn't match
awk '!/[a-z]/'     # !expr negates expr

Related Solutions

Sed one-liner to delete any line that begins with a digit

sed -e '/^[0-9]/d' filename > filename.new

or to modify in place

sed -i -e '/^[0-9]/d' filename

Grep/Sed/Awk – Print Line Only if Next Line Does Not Match

Here is an awk alternative:

awk '
  /^Starting/ { I[$5] = $0                  }
  /^ID/       { delete I[$2]                }
  END         { for (key in I) print I[key] }
' infile

Output:

Starting activity for ID 33367

The I associative array keeps track of what ids have been seen.

Best Answer

Related Solutions

Sed one-liner to delete any line that begins with a digit

Grep/Sed/Awk – Print Line Only if Next Line Does Not Match

Related Question