如何在旧版FreeBSD中修正日期参数格式化的脚本代码？

Got it, let's get that date formatting working for your old FreeBSD server. The issue here is that older versions of FreeBSD's date command uses a different syntax than newer FreeBSD releases or GNU date (the one you might be used to on Linux systems).

Your original command selected_date=$(date -j $1 +"%Y-%m-%d") fails because the old date requires you to explicitly define the input format of your date parameter using the -f flag when using -j for format conversion. Without -f, it tries to interpret your input as a system time to set (which isn't what you want, and will throw errors since you're not providing valid time-setting arguments).

Corrected Code #

Assuming your input date parameter ($1) is in the format YYYY-MM-DD (e.g., 2024-05-20), here's the fixed command:

selected_date=$(date -j -f "%Y-%m-%d" "$1" +"%Y-%m-%d")

Let's break down what each part does:

• -j: Tells date not to modify the system clock—we're only doing format conversion here.
• -f "%Y-%m-%d": Specifies the format of the input date string you're passing in ($1). This must exactly match the format of your input parameter.
• "$1": Your input date argument (always wrap this in quotes to avoid issues with spaces or special characters).
• +"%Y-%m-%d": The output format you want (you can adjust this if you need a different format later).

Adjusting for Different Input Formats #

If your input date uses a different format, just update the -f flag to match:

• For input like 05/20/2024 (MM/DD/YYYY):

  selected_date=$(date -j -f "%m/%d/%Y" "$1" +"%Y-%m-%d")
  

• For input like 20240520 (YYYYMMDD):

  selected_date=$(date -j -f "%Y%m%d" "$1" +"%Y-%m-%d")
  

Just make sure the -f format string aligns perfectly with how your input date is structured, and you'll be good to go!

内容的提问来源于stack exchange，提问作者Saeko