If you wish to determine the version of Firefox installed on an OS X from a command line interface (CLI), you can open a Terminal window and use the command shown below:
$ /Applications/Firefox.app/Contents/MacOS/firefox -v Mozilla Firefox 45.8.0 $
You can also find the information in the
Info.plist file found at
/Applications/Firefox.app/Contents/Info.plist. The version number
will be on the line following the "key" line for CFBundleGetInfoString
and also after the "key" line for CFBundleShortVersionString
.
<key>CFBundleGetInfoString</key>
<string>Firefox 45.8.0</string>
<key>CFBundleShortVersionString</key>
<string>45.8.0</string>
So I could find the version using the grep command.
$ grep -A 1 CFBundleShortVersionString /Applications/Firefox.app/Contents/Info.plist | grep string <string>45.8.0</string> $
If I just want to see the version number without the surrounding "string" tags, I can combine grep and sed commands as shown below:
$ grep -A 1 CFBundleShortVersionString /Applications/Firefox.app/Contents/Info.plist | grep string | sed -E -e 's/<\/?string>//g' 45.8.0
The command that I want sed to execute is contained within single
quotes. The s at the beginning of the command indicates I want
to perform a "substitute" operation. Within the first pair of forward
slashes (/), I place the string I want sed to replace.
Sed can use regular expressions. In a regular expression, the question
mark character indicates that the preceding element can be matched zero or
more times. Since I want to eliminate both <string>
and </string> I can put a question mark after a
forward slash, i.e., /?, to indicate I want to look for
both "string" and "/string". But, because I am using the forward slash to
separate the pattern for which I want sed to search and the replacement pattern,
i.e., s/pattern/new_pattern, I need to indicate to sed that I
want it to treat the forward slash before "string" as just a regular character,
so I need to "escape" the meaning it would normally assign to it with an
"escape
character," which is the backslash (\) character.
Since I want sed to eliminate the pattern it finds rather than replace it
with some other pattern, I can use s/pattern// to indicate that
it should eliminate the old pattern. By putting a g at the end
of the command, I indicate that I want sed to replace the pattern "globally"
on the line, i.e., not just for the first instance it finds, to ensure it
removes both <string> and </string>.
If I want to remove the whitespace before the version number, I need to remove the tab that precedes the version number. You can see that it is one tab character rather than multiple space characters by piping the output into the od utility as shown below:
$ grep -A 1 CFBundleShortVersionString /Applications/Firefox.app/Contents/Info.plist | grep string | sed -E -e 's/<\/?string>//g' | od -c 0000000 \t 4 5 . 8 . 0 \n 0000010
The \t represents the tab character and the \n
at the end of the line indicates a
newline
character. But sed doesn't recognize \t as representing the tab
character. However, I can tell it to look for the tab character from the
Terminal window's Bash shell interface by using ^V, i.e., by
hitting the control and v keys simultaneously followed by
hitting the tab key. You won't see any representation of
the tab character on the line, other than additional space appearing,
but sed then knows to look for the tab character. After hitting the tab
key, I can put an asterisk (*) which indicates in a regular
expression that the preceding element, e.g. a tab character in this case,
should be matched zero or more times.
$ grep -A 1 CFBundleShortVersionString /Applications/Firefox.app/Contents/Info.plist | grep string | sed -E -e 's/ *<\/?string>//g' 45.8.0 $
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