Get time by increasing or decreasing an hour in Linux command

Posted on November 16, 2014, 11:09 pm

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Some linux commands tips and tricks (get time by increasing/decreasing an hour in Linux command)

How to get time by -/+ an hour in Linux command ?

Bad command

echo $(date "+%Y%m%d")$(($(date "+%H")-1))

Why ? : the output format is only one digit from (0-9) for midnight (00h) you will have (00-1) -> WTF !

Good command
"OK but not the top one :/" and this one cans only decrease

echo $(date "+%Y%m%d")$(date +%H -d "1 hour ago")

Good command
"Yes, this one is perfect :)"

echo $(date "+%Y%m%d%H" -d "1 hour ago")   

Get time by increasing or decreasing an hour in Linux command

/!\with the same command you can decrease by day or year
Ex:

echo $(date "+%Y%m%d%H" -d "1 day ago") echo $(date "+%Y%m%d%H" -d "1 year ago")
echo $(date "+%Y%m%d%H" -d "1 day ago")
echo $(date "+%Y%m%d%H" -d "1 year ago")

How to list all file recursively?

find . -exec ls -dl \{\} \; | awk '{print $3, $4, $9}'

How to show the process by name ?

ps aux | grep non_du_processus_ou_non_du_script

How to show the directory with size ?

du -h /dir/size   
du -ch | grep total