What ##*/ does in bash? [duplicate] - bash

Question

I have a string like this:
/var/cpanel/users/joebloggs:DNS9=domain.example
I need to extract the username (joebloggs) from this string and store it in a variable.
The format of the string will always be the same with exception of joebloggs and domain.example so I am thinking the string can be split twice using cut?
The first split would split by : and we would store the first part in a variable to pass to the second split function.
The second split would split by / and store the last word (joebloggs) into a variable
I know how to do this in PHP using arrays and splits but I am a bit lost in bash.

Answer 1

To extract joebloggs from this string in bash using parameter expansion without any extra processes...
MYVAR="/var/cpanel/users/joebloggs:DNS9=domain.example"
NAME=${MYVAR%:*} # retain the part before the colon
NAME=${NAME##*/} # retain the part after the last slash
echo $NAME
Doesn't depend on joebloggs being at a particular depth in the path.
Summary
An overview of a few parameter expansion modes, for reference...
${MYVAR#pattern} # delete shortest match of pattern from the beginning
${MYVAR##pattern} # delete longest match of pattern from the beginning
${MYVAR%pattern} # delete shortest match of pattern from the end
${MYVAR%%pattern} # delete longest match of pattern from the end
So # means match from the beginning (think of a comment line) and % means from the end. One instance means shortest and two instances means longest.
You can get substrings based on position using numbers:
${MYVAR:3} # Remove the first three chars (leaving 4..end)
${MYVAR::3} # Return the first three characters
${MYVAR:3:5} # The next five characters after removing the first 3 (chars 4-9)
You can also replace particular strings or patterns using:
${MYVAR/search/replace}
The pattern is in the same format as file-name matching, so * (any characters) is common, often followed by a particular symbol like / or .
Examples:
Given a variable like
MYVAR="users/joebloggs/domain.example"
Remove the path leaving file name (all characters up to a slash):
echo ${MYVAR##*/}
domain.example
Remove the file name, leaving the path (delete shortest match after last /):
echo ${MYVAR%/*}
users/joebloggs
Get just the file extension (remove all before last period):
echo ${MYVAR##*.}
example
NOTE: To do two operations, you can't combine them, but have to assign to an intermediate variable. So to get the file name without path or extension:
NAME=${MYVAR##*/} # remove part before last slash
echo ${NAME%.*} # from the new var remove the part after the last period
domain

Answer 2

Define a function like this:
getUserName() {
echo $1 | cut -d : -f 1 | xargs basename
}
And pass the string as a parameter:
userName=$(getUserName "/var/cpanel/users/joebloggs:DNS9=domain.example")
echo $userName

Answer 3

What about sed? That will work in a single command:
sed 's#.*/\([^:]*\).*#\1#' <<<$string
The # are being used for regex dividers instead of / since the string has / in it.
.*/ grabs the string up to the last backslash.
\( .. \) marks a capture group. This is \([^:]*\).
The [^:] says any character _except a colon, and the * means zero or more.
.* means the rest of the line.
\1 means substitute what was found in the first (and only) capture group. This is the name.
Here's the breakdown matching the string with the regular expression:
/var/cpanel/users/ joebloggs :DNS9=domain.example joebloggs
sed 's#.*/ \([^:]*\) .* #\1 #'

Answer 4

Using a single Awk:
... | awk -F '[/:]' '{print $5}'
That is, using as field separator either / or :, the username is always in field 5.
To store it in a variable:
username=$(... | awk -F '[/:]' '{print $5}')
A more flexible implementation with sed that doesn't require username to be field 5:
... | sed -e s/:.*// -e s?.*/??
That is, delete everything from : and beyond, and then delete everything up until the last /. sed is probably faster too than awk, so this alternative is definitely better.

Answer 5

Using a single sed
echo "/var/cpanel/users/joebloggs:DNS9=domain.example" | sed 's/.*\/\(.*\):.*/\1/'

Answer 6

I like to chain together awk using different delimitators set with the -F argument. First, split the string on /users/ and then on :
txt="/var/cpanel/users/joebloggs:DNS9=domain.com"
echo $txt | awk -F"/users/" '{print$2}' | awk -F: '{print $1}'
$2 gives the text after the delim, $1 the text before it.

Answer 7

I know I'm a little late to the party and there's already good answers, but here's my method of doing something like this.
DIR="/var/cpanel/users/joebloggs:DNS9=domain.example"
echo ${DIR} | rev | cut -d'/' -f 1 | rev | cut -d':' -f1