Home » Fix or alternative for mktemp in OS X

Fix or alternative for mktemp in OS X

Solutons:


The following is what I ended up using to reliably create a temporary directory that works on both Linux and Darwin (all versions before Mac OS X 10.11), without hardcoding $TMPDIR or /tmp:

mytmpdir=$(mktemp -d 2>/dev/null || mktemp -d -t 'mytmpdir')

Background:

The GNU mktemp command requires no arguments. Plain mktemp will work and creates a temporary file in the system’s temporary directory.

Plain mktemp -d will create a directory instead of a file, which is what you’d want to use on Linux.

(gnu-coreutils)$ man mktemp
> ..
> If DIR is not specified, uses $TMPDIR if set, else /tmp.
> ..

By default, GNU mktemp uses the template tmp.XXXXXXXXXX for the name of the sub directory (or file). To customise this template, the -t option can be used.

OSX’s mktemp has no default template and requires a template to be specified. Unfortunately, where GNU mktemp takes the template as -t option, on OSX this is passed as positional argument. Instead, OSX’s mktemp has a -t option that means something else. The -t option on OSX is documented as a “prefix” for the template. It is expanded to {prefix}.XXXXXXXX, so it adds the Xs to it automatically (e.g. mktemp -d -t example could create example.zEJZWCTQ in the temp directory).

I was surprised to find that in many Linux environments, $TMPDIR is not set by default. Many CLI programs do support it when set, but still need a default for /tmp. This means passing $TMPDIR/example.XXXXXXXX to mktemp or mkdir is dangerous because it may produce /example.XXXXXXXX in the root directory of the local disk (due to $TMPDIR being unset and becoming an empty string).

On OSX, $TMPDIR is always set and (at least in the default shell) it is not set to /tmp (which is a symlink to /private/tmp) but to /var/folders/dx/*****_*************/T. So whatever we do for OSX, should honour that default behaviour.

In conclusion, the following is what I ended up using to reliably create a temporary directory that works on both Linux and Darwin (Mac OS X), without hardcoding either $TMPDIR or /tmp:

mytmpdir=$(mktemp -d 2>/dev/null || mktemp -d -t 'mytmpdir')

The first part is for Linux. This command will fail on Darwin (Mac OS X) with error status code 1 responding with “usage: …”. That’s why we ignore stderr and instead then execute the Mac variant. The mytmpdir prefix is only used on Mac (where that option is required to be set).

You have to supply a template. mktemp -d /tmp/foo.XXXX should work. I’ve never seen --directory. The -- suggests that it is a GNU extension.

Change --directory to -d. The former is a GNU-ism, but GNU mktemp from coreutils also supports -d. The mktemp in OS X is the same as from BSD, so -d should be pretty portable among systems that actually ship a mktemp program.

Related Solutions

Joining bash arguments into single string with spaces

[*] I believe that this does what you want. It will put all the arguments in one string, separated by spaces, with single quotes around all: str="'$*'" $* produces all the scripts arguments separated by the first character of $IFS which, by default, is a space....

AddTransient, AddScoped and AddSingleton Services Differences

TL;DR Transient objects are always different; a new instance is provided to every controller and every service. Scoped objects are the same within a request, but different across different requests. Singleton objects are the same for every object and every...

How to download package not install it with apt-get command?

Use --download-only: sudo apt-get install --download-only pppoe This will download pppoe and any dependencies you need, and place them in /var/cache/apt/archives. That way a subsequent apt-get install pppoe will be able to complete without any extra downloads....

What defines the maximum size for a command single argument?

Answers Definitely not a bug. The parameter which defines the maximum size for one argument is MAX_ARG_STRLEN. There is no documentation for this parameter other than the comments in binfmts.h: /* * These are the maximum length and maximum number of strings...

Bulk rename, change prefix

I'd say the simplest it to just use the rename command which is common on many Linux distributions. There are two common versions of this command so check its man page to find which one you have: ## rename from Perl (common in Debian systems -- Ubuntu, Mint,...

Output from ls has newlines but displays on a single line. Why?

When you pipe the output, ls acts differently. This fact is hidden away in the info documentation: If standard output is a terminal, the output is in columns (sorted vertically) and control characters are output as question marks; otherwise, the output is...

mv: Move file only if destination does not exist

mv -vn file1 file2. This command will do what you want. You can skip -v if you want. -v makes it verbose - mv will tell you that it moved file if it moves it(useful, since there is possibility that file will not be moved) -n moves only if file2 does not exist....

Is it possible to store and query JSON in SQLite?

SQLite 3.9 introduced a new extension (JSON1) that allows you to easily work with JSON data . Also, it introduced support for indexes on expressions, which (in my understanding) should allow you to define indexes on your JSON data as well. PostgreSQL has some...

Combining tail && journalctl

You could use: journalctl -u service-name -f -f, --follow Show only the most recent journal entries, and continuously print new entries as they are appended to the journal. Here I've added "service-name" to distinguish this answer from others; you substitute...

how can shellshock be exploited over SSH?

One example where this can be exploited is on servers with an authorized_keys forced command. When adding an entry to ~/.ssh/authorized_keys, you can prefix the line with command="foo" to force foo to be run any time that ssh public key is used. With this...

Why doesn’t the tilde (~) expand inside double quotes?

The reason, because inside double quotes, tilde ~ has no special meaning, it's treated as literal. POSIX defines Double-Quotes as: Enclosing characters in double-quotes ( "" ) shall preserve the literal value of all characters within the double-quotes, with the...

What is GNU Info for?

GNU Info was designed to offer documentation that was comprehensive, hyperlinked, and possible to output to multiple formats. Man pages were available, and they were great at providing printed output. However, they were designed such that each man page had a...

Set systemd service to execute after fstab mount

a CIFS network location is mounted via /etc/fstab to /mnt/ on boot-up. No, it is not. Get this right, and the rest falls into place naturally. The mount is handled by a (generated) systemd mount unit that will be named something like mnt-wibble.mount. You can...

Merge two video clips into one, placing them next to each other

To be honest, using the accepted answer resulted in a lot of dropped frames for me. However, using the hstack filter_complex produced perfectly fluid output: ffmpeg -i left.mp4 -i right.mp4 -filter_complex hstack output.mp4 ffmpeg -i input1.mp4 -i input2.mp4...

How portable are /dev/stdin, /dev/stdout and /dev/stderr?

It's been available on Linux back into its prehistory. It is not POSIX, although many actual shells (including AT&T ksh and bash) will simulate it if it's not present in the OS; note that this simulation only works at the shell level (i.e. redirection or...

How can I increase the number of inodes in an ext4 filesystem?

It seems that you have a lot more files than normal expectation. I don't know whether there is a solution to change the inode table size dynamically. I'm afraid that you need to back-up your data, and create new filesystem, and restore your data. To create new...

Why doesn’t cp have a progress bar like wget?

The tradition in unix tools is to display messages only if something goes wrong. I think this is both for design and practical reasons. The design is intended to make it obvious when something goes wrong: you get an error message, and it's not drowned in...