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I'm trying to use the curl command to access a http url with a exclamation mark (!) in its path. e.g:
curl -v "http://example.org/!287s87asdjh2/somepath/someresource"
the console replies with bash: ... event not found.
What is going on here? and what would be the proper syntax to escape the exclamation mark?
The exclamation mark is part of history expansion in bash. To use it you need it enclosed in single quotes (eg: 'http://example.org/!132').
You might try to directly escape it with a backslash (\) before the character (eg: "http://example.org/\!132"). However, even though a backslash before the exclamation mark does prevent history expansion, the backslash is not removed in such a case. So it's better to use single quotes, so you're not passing a literal backslash to curl as part of the URL.
"http://example.org/\!132" actually expands without interpreting the backslash (POSIX compliance reasons, I believe).
Mar 3, 2012 at 19:14
\! and double quotes.
| and is used to create a pipe. If you're sending scripts to customers and can't be sure what shell they'll run it in, you have to test with them all!
Jan 16, 2018 at 9:47
As well as the answer given by Daniel, you can also simply turn off history expansion altogether if you don't use it with set +H.
Ctrl-R) that let you preview & edit your command so you don't blindly fire away with command !-14 that you though was at !-12 that, oops, happened to be rm -rf *. Be safe. Disable history expansion! Eschew the !!
fc -14 instead. But it's true that you can do that without history expansion being enabled also. Personally, I use !$ and !vi and sudo !! and even git add !vi:$ often enough to warrant leaving history expansion enabled.
set +o histexpand; see also superuser.com/a/133782
I would personally do single quotes, but for completeness, I will also note since it is a URL, you can encode the ! as %21, e.g. curl -v http://example.org/%21132 .
This also can do
curl -v "http://example.org/"'!'"287s87asdjh2/somepath/someresource"
or
curl -v "http://example.org/"\!"287s87asdjh2/somepath/someresource"
Which works because bash concatenates adjacent strings. This approach is particularly useful when you have other things that need shell expansion, so you can't use single quotes for the entire string:
curl -v 'http://example.org/!'"287s87asdjh2/${basepath}/someresource"
! character is used for history expansions in command line prompt.
so this can be a problem in prompt but not in shell script files.
as you can see history expansions work even in double quotes.
I have come across the same problem, and my simple solution was to use a variable:
E=!
curl -v "http://example.org/${E}287s87asdjh2/somepath/someresource"
Here the simplicity is that (1) It is portable across shells and commands (2) Does not require knowing escape syntax and ASCII codes.
Ever since Bash 4.3, you can now use double quotes to quote the history expansion character (edit: as long as the the exclamation mark is at the end of the string or followed by a space)
$ $SHELL --version
GNU bash, version 4.3...
[...]
$ echo "Hello World!"
Hello World!
$ echo "Hello! World"
Hello! World
$ echo "Hello!World"
bash: !World: event not found
$ echo 'Hello!World'
Hello!World
echo, echo seems to handle this differently on its own
echo "Hi! Hello." also works as intended.
Nov 22, 2021 at 4:33
To those who are using git bash in windows, the accepted answer from @DanielPittman works. However, you should replace the backslash (\) with a forward slash (/).
For example, in unix, it'd look something like this:
curl https://abc.com/services -H 'Authorization: Bearer 111A80BBZZCnS\!ZR412543s'
For windows, it'd be something like this (focus on the forward slash in the authorization header part)
curl https://abc.com/services -H 'Authorization: Bearer 111A80BBZZCnS/!ZR412543s'
"foo!"not invoke history expansion, but"foo!123"still does.