Problem Analysis
This question has two core knowledge points:
1. How to automatically indicate today's date 2. Disk Usage
Date print command to date, examples of commands as follows:
DATE # 2017 Nian 12 Wednesday, 20 September 16:26:55 CST
And the title should be required format: 2017-12-20, date order is such a function, the example command follows:
DATE Y-% +% # M-% D 2017-12-20 or: #% F. + DATE 2017-12-20
Disk usage, we use the command df -h to achieve, the following example command:
# Df -h file system capacity has been available with a mount point with% / dev / 2% Vdal 99G 92G 1.8G / devtmpfs 911M 0 911M 0% / dev tmpfs 920M 0 920M 0% / dev / SHM tmpfs 920M 920M 336K. 1 % / RUN tmpfs 920M 0 920M 0% / SYS / FS / a cgroup tmpfs 184M 0 184M 0% / RUN / User / 0
With the above analysis later, we finally get the answer to this question:
#! /bin/bash d=`date +%F` logfile=$d.log df -h > $logfile
The current date assigned to the variable d, to define the daily log file name, the final result of the use of disk input directly to the log. Here>, it can compare the results of the special symbol to the left of the file is written to the right of the sign in.
1. the shell Anti quotation marks represent the results of a command, usually variables are assigned, sample command is as follows:
# n=`wc -l /etc/passwd|awk '{print $1}'`
# echo $n
23
2. date command has many uses, for example:
# Date +% H ## hours 16 # DATE + M% ## min 38 is # DATE seconds + ##% S 55 # DATE + ##% T time 16:39:31 # DATE% W + ## weeks 3 # date -d "-1 day" +% F ## one day before 2017-12-19
3> is redirected, we run a command, have the right information is also output an error message output,> will correct output information is written to the specified file, there is a corresponding error redirection symbol 2 >, as the name suggests it will error information is written to the specified file. Examples are as follows:
# Ls / etc / passwd / etc / nofile ## in which the / etc / nofile does not exist, it will complain ls: can not access the / etc / nofile: No such file or directory / etc / passwd # LS / etc / passwd / etc / nofile> / tmp / log 2> / tmp / error # CAT / tmp / log / etc / passwd # CAT / tmp / error LS: can not access the / etc / nofile: no such file or directory