I have bash shell script to modify string.
I want get 14040116 (YYMMDDHH) from string 44[tip] 3764d6b8ae82 2014-04-01 16:34 +0400 igor
My current script looks like
raw_info="44[tip] 3764d6b8ae82 2014-04-01 16:34 +0400 igor"
hg_date=`echo $raw_info | cut -d' ' -f 3`
hg_date=${hg_date//-/}
hg_date=${hg_date:2}
hg_hour=`echo $raw_info | cut -d' ' -f 4 | cut -d':' -f 1`
hg_rev=${hg_date}${hg_hour}
It works, but can it be shorter?
Here is an awk solution.
echo "44[tip] 3764d6b8ae82 2014-04-01 16:34 +0400 igor" | awk '{split($3,a,"-");split($4,b,":");print substr(a[1],3,2)a[2]a[3]b[1]}'
14040116
split($3,a,"-") divides the 3rd field by -, so 2014-04-01 gives a[1]=2014, a[2]=04, a[3]=01.split($4,b,":")divides the 4th field by :, so 16:34 gives b[1]=16, b[2]=34.Then print:
substr(a[1],3,2) gives last two digits of 2014, that is, 14.a[2]a[3]b[1] gives 14040116.You can get the specific part of the string where the date is and then use date format controls to print it properly:
$ raw_info="44[tip] 3764d6b8ae82 2014-04-01 16:34 +0400 igor"
$ date -d"$(cut -d' ' -f3-4 <<< "$raw_info")" "+%y%m%d%H"
14040116
To store it into a variable, nest $():
$ hg_rev=$(date -d"$(cut -d' ' -f3-4 <<< "$raw_info")" "+%y%m%d%H")
$ echo "$hg_rev"
14040116
By pieces:
$ cut -d' ' -f3-4 <<< "$raw_info" #get 3rd and 4th fields from the string
2014-04-01 16:34
$ date -d"2014-04-01 16:34" "+%y%m%d%H" #convert date into YYMMDDHH format
14040116
as from man date:
%y last two digits of year (00..99)
%m month (01..12)
%d day of month (e.g., 01)
%H hour (00..23)
While (IMHO) @fedorqui's solution is the best, you can also employ sed, eg.
sed 's/.* \(2.\)\(..\)-\(..\)-\(..\) \(..\):.*/\2\3\4\5/' <<<"$raw_info"
what prints
14040116
Ps: it depends on two-digit format and 2xxx year
Every solution given thus far is invoking external commands, and thus needlessly inefficient.
The much more efficient approach is to use bash's built-in string manipulation tooling.
raw_info="44[tip] 3764d6b8ae82 2014-04-01 16:34 +0400 igor"
read -r tip_name hash ymd hour _ <<<"$raw_info"
hg_rev="${ymd:2:2}${ymd:5:2}${ymd:8:2}${hour%%:*}"
