if语句中的未知错误

Question

我的bash脚本中的if语句中出现未知错误：

Bash脚本：

#!/bin/bash

TIMESTAMP=$(date +"%Y-%m-%d_%H%M")
DAY=$(date +"%Y-%m-%d")
LUDAY=$(date +"%Y/%m/%d")
LUTIME=$(date +"%H:%M:%S")
mkdir /home/pi/Documents/Webcam/Shots/$DAY
fswebcam -d v4l2:/dev/video0 -r 1720x1280 --no-banner /home/pi/Documents/Webcam/Shots/$DAY/$TIMESTAMP.jpg /home/pi/Documents/Webcam/Shots/Live/Live.jpg
sudo cp /home/pi/Documents/Webcam/Shots/$DAY/$TIMESTAMP.jpg /usr/share/apache2/icons/Live.jpg
timesincelastmod=$(expr $(date +%s) - $(date +%s -r /var/www/html/index.html))
declare -i delay=10
TIMESINCELASTMOD=$(($timesincelastmod+0))
if [$TIMESINCELASTMOD \< $delay]; then
  sed -i -e "s|\(Lastupdate:\).*\(.\)|\1 $LUDAY at $LUTIME (CEST) \2|g" /var/www/html/index.html
else
  sed -i -e "s|\((CEST)\).*\(.\)|\1 - (Failed to upload last photo) \2|g" /var/www/html/index.html
fi

错误：

pi@JayRasp:/usr/lib/apache2/modules $ sudo bash /home/pi/Documents/Webcam/update_pic.sh
--- Opening v4l2:/dev/video0...
/dev/video0 opened.
No input was specified, using the first.
Adjusting resolution from 1720x1280 to 1600x1200.
--- Capturing frame...
Captured frame in 0.00 seconds.
--- Processing captured image...
Disabling banner.
Writing JPEG image to '/home/pi/Documents/Webcam/Shots/2016-07-07/2016-07-07_0659.jpg'.
Writing JPEG image to '/home/pi/Documents/Webcam/Shots/Live/Live.jpg'.
/home/pi/Documents/Webcam/update_pic.sh: line 13: [1805: command not found

Answer 1

[和]周围需要空格。

为什么？

[是一个命令。

tim@Hairy16:~$ ls /usr/bin
[

尝试if [ $TIMESINCELASTMOD \< $delay ]; then

在bash中，命令需要它们周围的空格。

此外，您需要在-lt或{{{{}}之前使用-gt，-le，-ge和\代替< 1}}。它们意味着小于，大于，小于或等于和大于或等于。