tr command can be used to translate, squeeze and delete character
man tr and
IEEE Std 1003.1-2017-tr for the full specification.
tr, unlike most other utilities, only reads from standard input and only writes to standard output. Therefore, you will have to use
tr [options] < input > output.
tr operates in a number of modes, depending upon the invocation:
- Deleting characters
To delete all occurrences of certain characters, use
tr -d asdf.
- Deleting repeated characters
To replace repeated characters with a single character ('squeeze'), use
tr -s asdf.
- Transliterating characters
To replace all 'a' characters with '1', all 'b' with '2' and all 'c' with
tr abc 123.
Certain special forms are allowed for the arguments.
a-z expands to all
characters from 'a' to 'z',
\t represents a tab and so on. See the
documentation for a full list.