tr

Overview ¶

Package tr implements the tr builtin command.

tr — translate, squeeze, and/or delete characters

Usage: tr [OPTION]... SET1 [SET2]

Translate, squeeze, and/or delete characters from standard input, writing to standard output.

Accepted flags:

-d, --delete
    Delete characters in SET1; do not translate.

-s, --squeeze-repeats
    Replace each sequence of a repeated character that is listed
    in the last specified SET with a single occurrence of that
    character.

-c, -C, --complement
    Use the complement of SET1 (all byte values NOT in SET1).

-t, --truncate-set1
    First truncate SET1 to the length of SET2 when translating.

-h, --help
    Print this usage message to stdout and exit 0.

SET notation:

Ranges:             a-z, A-Z, 0-9
Character classes:  [:alnum:], [:alpha:], [:blank:], [:cntrl:],
                    [:digit:], [:graph:], [:lower:], [:upper:],
                    [:print:], [:punct:], [:space:], [:xdigit:]
Equivalence class:  [=c=]  (matches the literal character c)
Repeat:             [c*n]  (repeat char c, n times; [c*] fills, SET2 only)
Backslash escapes:  \a \b \f \n \r \t \v \\ \NNN (octal)

Exit codes:

0  Success.
1  Error (invalid arguments, read error, etc.).

Memory safety:

tr operates on a byte-at-a-time basis using a 256-entry lookup
table. Input is read in fixed-size chunks (32 KiB). No allocation
is proportional to input size. All loops check ctx.Err() to honour
the shell's execution timeout.