Msgid

msgid is a label used in GNU gettext localization to identify the original text to be translated within portable object (.po) files. It serves as the key or source string that the program will look up and translate into the target language at runtime.

In a .po file, each translatable entry typically includes an optional context (msgctxt), a msgid, and one or more msgstr values. The msgid contains the source text in the base language (often English). For plural forms, msgid_plural holds the plural form, and translations use msgstr[0], msgstr[1], etc. The msgid can be split over multiple lines by using adjacent quoted strings; these are concatenated when read by the gettext tools.

Example:

msgid "File not found"

msgstr "Datei nicht gefunden"

Plural example:

msgid "There is one item."

msgid_plural "There are %d items."

msgstr[0] "Es gibt einen Artikel."

msgstr[1] "Es gibt %d Artikel."

In addition, msgctxt provides disambiguation when the same source string has different meanings in different contexts, and is used as part of the lookup when present. Tools such as xgettext extract msgid entries from source code, while msgfmt compiles .po files into binary .mo files used at runtime. In code, libraries typically expose a function like gettext or a wrapper such as _() to retrieve the translated string using the msgid as the key.