zsh: strftime command not found

Question

I am currently learning the zsh and now I wanted to use strftime but i get:

zsh: command not found: strftime

I think I'm doin' something wrong, since I see people using that function all the time in their dotfiles.

Paronymous

Answer 1

strftime is defined in a zsh module called datetime. The zmodload command loads modules from a colon-separated list of directories in $module_path.

On my system:

% echo $module_path
/usr/lib/zsh/4.3.10
% ls -l $module_path
drwxr-xr-x 3 root root 4096 2009-11-05 01:03 zsh
% ls -l $module_path/zsh/datetime*
-rw-r--r-- 1 root root 9828 2009-09-10 02:45 /usr/lib/zsh/4.3.10/zsh/datetime.so
% type -a strftime
strftime not found
% zmodload zsh/datetime
% strftime %Y-%m-%d 1271603087
2010-04-18
% type -a strftime
strftime is a shell builtin
% /bin/date -d @1271603087 +%Y-%m-%d
2010-04-18

Paraph

Answer 2

For anyone who arrives here via Google, there's now a way to do this that doesn't require a zmodload. (I use it to detect when .zshrc is slow due to resource contention, so I don't want it to add new filesystem requests.)

${(%):-"%D{STRFTIME_STRING_HERE}"}

The gist of it is as follows:

1. Zsh allows ${VAR:-DEFAULT} parameter substitution without a VAR.
2. Putting (%) before VAR enables expansion of the substitution tokens used in PS1 and friends. (This is a very powerful feature because it also grants access to things like %F{green}. See "expansion of prompt sequences" in man zshmisc for more.)
3. Within a prompt-expanded string, %D{...} invokes strftime(3).

I find %D{%s} particularly useful because %s retrieves the "seconds since the epoch" timestamp, which you can then do arithmetic on.

(Just be aware that, while %s is supported on Linux, AIX, Illumos, MINIX, OSX, and all BSD-family systems, it's not part of POSIX and isn't listed as supported in the online strftime documentation for Solaris, HP-UX, UnixWare, OpenServer, or the Windows libraries Cygwin and MinGW depend on.)

Kaylyn

Answer 3

strftime is a C function, I believe date has all the same functionality on the command line.

See man date for more.

One uses the --date=STRING option to specify a date to format instead of getting current time.

Wineshop