The accepted answer only takes into account ANSI Standardized escape sequences that are formatted to alter foreground colors & text style. Removing those would require additional work outside the scope of this answer. Note that the above regex only removes the ANSI C1 codes, however, and not any additional data that those codes may be marking up (such as the strings sent between an OSC opener and the terminating ST code). And beyond CSI, there are codes to select alternative fonts ( SS2 and SS3), to send 'private messages' (think passwords), to communicate with the terminal ( DCS), the OS ( OSC), or the application itself ( APC, a way for applications to piggy-back custom control codes on to the communication stream), and further codes to help define strings ( SOS, Start of String, ST String Terminator) or to reset everything back to a base state ( RIS). With CSI alone you can also control the cursor, clear lines or the whole display, or scroll (provided the terminal supports this of course). However, there is more to ANSI than just CSI SGR codes. 0 (or 00 in this example): reset, disable all attributes.So for each \x1B[.m sequence, the 3 codes that are used are: The parameters (separated by semicolons) in between those tell your terminal what graphic rendition attributes to use. The example you gave contains 4 CSI (Control Sequence Introducer) codes, as marked by the \x1B[ or ESC [ opening bytes, and each contains a SGR (Select Graphic Rendition) code, because they each end in m. ECMA-48 standard, 5th edition (especially sections 5.3 and 5.3). the ANSI escape codes overview on Wikipedia.Which can be condensed down to # 7-bit and 8-bit C1 ANSI sequencesĪnsi_escape_8bit = ansi_escape_8bit.sub(b'', somebytesvalue) Result = ansi_escape_8bit.sub(b'', somebytesvalue) (?: # either 7-bit C1, two bytes, ESC Fe (omitting # or a single 8-bit byte Fe (omitting CSI) If you do need to cover the 8-bit codes too (and are then, presumably, working with bytes values) then the regular expression becomes a bytes pattern like this: # 7-bit and 8-bit C1 ANSI sequences The latter are never used in today's UTF-8 world where the same range of bytes have a different meaning. The above regular expression covers all 7-bit ANSI C1 escape sequences, but not the 8-bit C1 escape sequence openers. Or, without the VERBOSE flag, in condensed form: ansi_escape = ansi_escape.sub('', sometext) (?: # 7-bit C1 Fe (except # or [ for CSI, followed by a control sequence Finally, we compare the normal and escaped version to determine whether we need to escape this character and output the result if we do.Delete them with a regular expression: import re After that, with the help of the %q format modifier, we get an escaped version of the character. Next, this value is reused in printf with a prefix to get the resulting character. For each, it uses printf to extract and compare each character with its escaped form.įirst, %o returns the octal form of the character’s code. The snippet above goes through the first 128 characters in the ASCII table. The characters we would need to escape in that instance are in the output of the following script: $ for code in " Recall our discussion of writing strings without quotes. The standard built-in printf (Print Function) command also has its own special character. Let’s now explore how Bash treats sequences without any quotes. This simply means that we can spread a string over several lines without adding newline characters to it: $ text="a \ disabling history expansion via set +o histexpandįinally, the combination is ignored and removed from double-quoted strings.enclosing it in single quotes to escape an.using it at the end of a string or before whitespace characters.prefixing it with a backslash (which remains, same as with a normal character like ).Importantly, the is an exceptional character, the special meaning of which can be ignored by: ~, when beginning a string, to avoid tilde expansion and confusion with the $HOME directoryįurthermore, the prefix is not stored in the string when preceding all but one () of the characters above: $ text="!event".!, when history expansion is enabled outside POSIX mode, usually the case.\, when prefixing a character in this list except.newline, which is equivalent to under Linux.
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