tr – Translate or Delete characters
Summary :
tr will Translate, squeeze, and/or delete characters from stdin, writing to stdout.
Examples :
$ echo “fslog” | tr “fs” “FS” — Translate f to F & s to S.
$ echo “fslog” | tr “[a-z]” “[A-Z]” — Change case (lower to upper)
$ echo “HelloooOOOoooo” | tr -s ‘[:lower:]’ — Squeez the “lower” case letters.
$ echo “FxSyLzoyg” | tr -d xyz — Remove xyz
$ cat myfile | tr -s ‘n’ — Remove repeated new lines.
$ echo “ABCDEFG” | tr -c “ACEG” “n” — Expect “ACEG” translate others to newline char.
‘tr’ supports few std esc sequences, regular expressions, char classes
(lower, upper, space, blank, alpha,…), etc.
Read : man tr