Linux filter control character command expand
The expand command converts the tab key into a space character. It is a member of the pipeline command family.
Regarding expand, we will introduce an option
-t NUM Convert the tab key to NUM spaces instead of the default 8 spaces.
Same as col command, here we also use bird brother example
# grep '^MANPATH' /etc/man.config | head -n 3 | \
> expand -t 6 - | cat -A
MANPATH /usr/man$
MANPATH /usr/share/man$
MANPATH /usr/local/man$
123456123456123456.....
# Take a closer look at the numbers above, because I use 6 characters to represent the length of a [tab], so,
# there will be 12 (two [tab]) characters between MAN... and /usr! If tab is changed to 9,
# the situation will be different! This is not easy to understand~ You can configure a few more numbers to check and you will know!
Here is a quote from Bird Brother
expand is also fun~ It will automatically convert [tab] into space bar~ So, in the example above, using cat -A will not find the ^I character~ In addition, the biggest function of [tab] is to arrange the format neatly! After we convert it to the space bar, the size of this space bar will also be increased according to our own definition~ So, not one ^I will be replaced by 8 spaces! Pay special attention to this point! In addition, you can also refer to the unexpand command function that converts spaces into [tab]! ^_^
Since I have rarely used the expand command and don't have a deep understanding of it, I would like to borrow the work of Bird Brother. I hope it will be helpful to you.
For reprinting, please send an email to 1244347461@qq.com for approval. After obtaining the author's consent, kindly include the source as a link.
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