Given the following substring given obtained from the command df /dev/sdb1 | tail -n 1 :
/dev/sdb1 1952971772 1441131032 511840740 74% /media/kaiman/ShareData
I'd like to extract 1952971772 and 74% from that string, to use it in a bash script.
I know I could use some cut commands or something, but it won't work anymore if a size changes, for example.
I also had thoughts about using a regex or something, but I'd like to have the most recommended approach.
Thanks in advance!
As @kevin stated, you can use awk to select only the last line and avoid using tail at all by using END and also if you want to print two columns at once you can do this:
df /dev/sdb1 | awk 'END {print $2,$5}'
1952971772 74%
You can select the 2nd columns only:
$ df /dev/sdb1 | tail -1 | awk '{print $2}'
1952971772
Where $2 indicates the position of TAB separated columns. You can use cut because it handle only one occurrence of TAB and here there are multiples TABs to delimita a column.
END block so instead of using tail just use awk 'END { print $2,$5}'
$ df /dev/sdb1 | awk '{ print $5 }' | tail -n 1
for the percentage and
$ df /dev/sdb1 | awk '{ print $2 }' | tail -n 1
for the size.
Without the tail:
df /home | awk 'NR==2 { print $2 }'
df /home | awk 'NR==2 { print $5 }'
awk '{ print $2 }'
gets the 2nd column where multiple separators count as 1. So the 2nd column is always the same for your system for the 1st part of the command.
NR gives you the total number of records being processed or the line number.
df /home | awk '{print $2; print $5;}'.
Apr 30, 2019 at 13:26
END block so instead of using tail just use awk 'END { print $2,$5}'
dfin particular? If the latter, you can specify particular output fields explicitly e.g.df --output=pcent /dev/sdb1cuton character position on line which makes it fail when line length changes with fluctuations in file size. I believe you can tellcutto select column2and column5delineated by spaces but I'm on phone and can't research and effectively post an answer.cutwill see one column after each delimiter.