Linux Command - tr

The Linux tr command can be used to translate characters.

Swap any instance of ‘a’ for ‘b’:

echo "Test abc" | tr a b

Swap char in one set with corresponding char in second set:

echo "Test abc" | tr es xy
echo "Test abc" | tr abcd wxyz

Delete any characters in this set:

echo "Tests "  | tr -d est

Compress identical, consecutive chars:

echo "Tests eeee"| tr -s e

Change lower case to upper case:

echo "Testee"| tr "[:lower:]" "[:upper:]"

Use these to translate:

CHAR1-CHAR2	all characters from CHAR1 to CHAR2 in ascending order
[CHAR*]	in SET2, copies of CHAR until length of SET1
[CHAR*REPEAT]	REPEAT copies of CHAR, REPEAT octal if starting with 0
[:alnum:]	all letters and digits
[:alpha:]	all letters
[:blank:]	all horizontal whitespace
[:cntrl:]	all control characters
[:digit:]	all digits
[:graph:]	all printable characters, not including space
[:lower:]	all lower case letters
[:print:]	all printable characters, including space
[:punct:]	all punctuation characters
[:space:]	all horizontal or vertical whitespace
[:upper:]	all upper case letters
[:xdigit:]	all hexadecimal digits
[=CHAR=]	all characters which are equivalent to CHAR