test1="one two three four five"
echo $test1 | cut -d $'\t' -f2
I have a string which separated by TAB, and I want to get the second word by cut command.
I've found the question How to split a string in bash delimited by tab. But the solution is not used with cut.
This is happening because you need to quote $test1 when you echo:
echo "$test1" | cut -d$'\t' -f2
Otherwise, the format is gone and the tabs converted into spaces:
$ s="hello bye ciao"
$ echo "$s" <--- quoting
hello bye ciao
$ echo $s <--- without quotes
hello bye ciao
You don't need cut and can save yourself a fork:
$ test1=$(printf "one\ttwo\three\tfour\tfive")
$ read _ two _ <<< "${test1}"
$ echo "${two}"
two
Try to use cut without any -d option:
echo "$test1" | cut -f2
Below is expert from cut man page:
-d, --delimiter=DELIM
use DELIM instead of TAB for field delimiter
I run this:
test1="one;two;three;four;five"
echo $test1 | cut -d \; -f2
and get:
two
and your example:
test1="one two three four five"
echo $test1 | cut -d \t -f2
and get:
wo
Hope that helpful.
It's the problem of \t I think.
Related
I'm trying to print domain and topLeveldomain variables (example.com)
$line = example.com
domain =$line | cut -d. -f 1
topLeveldomain = $line | cut -d. -f 2
However when I try and echo $domain, it doesn't display desired value
test.sh: line 4: domain: command not found
test.sh: line 5: topLeveldomain: command not found
I suggest:
line="example.com"
domain=$(echo "$line" | cut -d. -f 1)
topLeveldomain=$(echo "$line" | cut -d. -f 2)
The right code for this should be:
line="example.com"
domain=$(echo "$line" | cut -d. -f 1)
topLeveldomain=$(echo "$line" | cut -d. -f 2)
Consider the right syntax of bash:
variable=value
(there are no blanks allowed)
if you want to use the content of the variable you have to add a leading $
e.g.
echo $variable
You don't need external tools for this, just do this in bash
$ string="example.com"
# print everything upto first de-limiter '.'
$ printf "${string%%.*}\n"
example
# print everything after first de-limiter '.'
$ printf "${string#*.}\n"
com
Remove spaces around =:
line=example.com # YES
line = example.com # NO
When you create a variable, do not prepend $ to the variable name:
line=example.com # YES
$line=example.com # NO
When using pipes, you need to pass standard output to the next command. Than means, you usually need to echo variables or cat files:
echo $line | cut -d. -f1 # YES
$line | cut -d. -f1 # NO
Use the $() syntax to get the output of a command into a variable:
new_variable=$(echo $line | cut -d. -f1) # YES
new_variable=echo $line | cut -d. -f1 # NO
I would rather use AWK:
domain="abc.def.hij.example.com"
awk -F. '{printf "TLD:%s\n2:%s\n3:%s\n", $NF, $(NF-1), $(NF-2)}' <<< "$domain"
Output
TLD:com
2:example
3:hij
In the command above, -F option specifies the field separator; NF is a built-in variable that keeps the number of input fields.
Issues with Your Code
The issues with your code are due to invalid syntax.
To set a variable in the shell, use
VARNAME="value"
Putting spaces around the equal sign will cause errors. It is a good
habit to quote content strings when assigning values to variables:
this will reduce the chance that you make errors.
Refer to the Bash Guide for Beginners.
this also works:
line="example.com"
domain=$(echo $line | cut -d. -f1)
toplevel=$(cut -d. -f2 <<<$line)
echo "domain name=" $domain
echo "Top Level=" $toplevel
You need to remove $ from line in the beginning, correct the spaces and echo $line in order to pipe the value to cut . Alternatively feed the cut with $line.
I have the following line in bash:
echo "Manufacturer: $(echo ${family:-$name}|cut -d' ' -f1)"
I would like to capitalize the echoed string using the ${var^} syntax but not sure how to add this to the current line. Can someone please suggest how to do this?
two one liners
$ echo "watever" | awk '{print toupper($0)}'
$ echo "watever" | tr '[:lower:]' '[:upper:]'
Just store above command's output in a variable using command substitution:
s=$(echo "Manufacturer: $(echo ${family:-$name}|cut -d' ' -f1)")
and then use:
echo "${s^^}"
to capitalize the string.
sed is handy here:
name=smith
family=""
echo "Manufacturer: $(sed 's/[^[:blank:]]\+/\U&/' <<< "${family:-$name}")"
Manufacturer: SMITH
If you only want to "title-case" it ("Manufacturer: Smith"), use \u instead of \U
I have entries of the form: cat:rat and I would like to assign them to separate variables in bash. I am currently able to do this via:
A=$(echo $PAIR | tr ':' '\n' | head -n1)
B=$(echo $PAIR | tr ':' '\n' | tail -n1)
after which $A and $B are, respectively, cat and rat. echo, the two pipes and all feels a bit like overkill am I missing a much simpler way of doing this?
Using the read command
entry=cat:rat
IFS=: read A B <<< "$entry"
echo $A # => cat
echo $B # => rat
Yes using bash parameter substitution
PAIR='cat:rat'
A=${PAIR/:*/}
B=${PAIR/*:/}
echo $A
cat
echo $B
rat
Alternately, if you are willing to use an array in place of individual variables:
IFS=: read -r -a ARR <<<"${PAIR}"
echo ${ARR[0]}
cat
echo ${ARR[1]}
rat
EDIT: Refer glenn jackman's answer for the most elegant read-based solution
animal="cat:rat"
A=echo ${animal} | cut -d ":" -f1
B=echo ${animal} | cut -d ":" -f2
might not be the best solution. Just giving you a possible solution
I'm developing a little script using ash shell (not bash).
Now i have a variable with the following composition:
VARIABLE = "number string status"
where number could be any number (actually between 1 and 18 but in the future that number could be higher) the string is a name and status is or on or off
The name usually is only lowercase letter.
Now my problem is to read only the string content in the variable, removing the number and the status.
How i can obtain that?
Two ways; one is to leverage $IFS and use a while loop - this will work for a single line quite happily - as:
echo "Part1 Part2 Part3" | while read a b c
do
echo $a
done
alternatively, use cut as follows:
a=`echo $var | cut -d' ' -f2`
echo $a
How about using cut?
name=$(echo "$variable" | cut -d " " -f 2)
UPDATE
Apparently, Ash doesn't understand $(...). Hopefully you can do this instead:
name=`echo "$variable" | cut -d " " -f 2`
How about :
name=$(echo "$variable" | awk '{print $2}')
#!/bin/sh
myvar="word1 word2 word3 wordX"
set -- $myvar
echo ${15} # outputs word 15
Suppose I have the string 1:2:3:4:5 and I want to get its last field (5 in this case). How do I do that using Bash? I tried cut, but I don't know how to specify the last field with -f.
You can use string operators:
$ foo=1:2:3:4:5
$ echo ${foo##*:}
5
This trims everything from the front until a ':', greedily.
${foo <-- from variable foo
## <-- greedy front trim
* <-- matches anything
: <-- until the last ':'
}
Another way is to reverse before and after cut:
$ echo ab:cd:ef | rev | cut -d: -f1 | rev
ef
This makes it very easy to get the last but one field, or any range of fields numbered from the end.
It's difficult to get the last field using cut, but here are some solutions in awk and perl
echo 1:2:3:4:5 | awk -F: '{print $NF}'
echo 1:2:3:4:5 | perl -F: -wane 'print $F[-1]'
Assuming fairly simple usage (no escaping of the delimiter, for example), you can use grep:
$ echo "1:2:3:4:5" | grep -oE "[^:]+$"
5
Breakdown - find all the characters not the delimiter ([^:]) at the end of the line ($). -o only prints the matching part.
You could try something like this if you want to use cut:
echo "1:2:3:4:5" | cut -d ":" -f5
You can also use grep try like this :
echo " 1:2:3:4:5" | grep -o '[^:]*$'
One way:
var1="1:2:3:4:5"
var2=${var1##*:}
Another, using an array:
var1="1:2:3:4:5"
saveIFS=$IFS
IFS=":"
var2=($var1)
IFS=$saveIFS
var2=${var2[#]: -1}
Yet another with an array:
var1="1:2:3:4:5"
saveIFS=$IFS
IFS=":"
var2=($var1)
IFS=$saveIFS
count=${#var2[#]}
var2=${var2[$count-1]}
Using Bash (version >= 3.2) regular expressions:
var1="1:2:3:4:5"
[[ $var1 =~ :([^:]*)$ ]]
var2=${BASH_REMATCH[1]}
$ echo "a b c d e" | tr ' ' '\n' | tail -1
e
Simply translate the delimiter into a newline and choose the last entry with tail -1.
Using sed:
$ echo '1:2:3:4:5' | sed 's/.*://' # => 5
$ echo '' | sed 's/.*://' # => (empty)
$ echo ':' | sed 's/.*://' # => (empty)
$ echo ':b' | sed 's/.*://' # => b
$ echo '::c' | sed 's/.*://' # => c
$ echo 'a' | sed 's/.*://' # => a
$ echo 'a:' | sed 's/.*://' # => (empty)
$ echo 'a:b' | sed 's/.*://' # => b
$ echo 'a::c' | sed 's/.*://' # => c
There are many good answers here, but still I want to share this one using basename :
basename $(echo "a:b:c:d:e" | tr ':' '/')
However it will fail if there are already some '/' in your string.
If slash / is your delimiter then you just have to (and should) use basename.
It's not the best answer but it just shows how you can be creative using bash commands.
If your last field is a single character, you could do this:
a="1:2:3:4:5"
echo ${a: -1}
echo ${a:(-1)}
Check string manipulation in bash.
Using Bash.
$ var1="1:2:3:4:0"
$ IFS=":"
$ set -- $var1
$ eval echo \$${#}
0
echo "a:b:c:d:e"|xargs -d : -n1|tail -1
First use xargs split it using ":",-n1 means every line only have one part.Then,pring the last part.
Regex matching in sed is greedy (always goes to the last occurrence), which you can use to your advantage here:
$ foo=1:2:3:4:5
$ echo ${foo} | sed "s/.*://"
5
A solution using the read builtin:
IFS=':' read -a fields <<< "1:2:3:4:5"
echo "${fields[4]}"
Or, to make it more generic:
echo "${fields[-1]}" # prints the last item
for x in `echo $str | tr ";" "\n"`; do echo $x; done
improving from #mateusz-piotrowski and #user3133260 answer,
echo "a:b:c:d::e:: ::" | tr ':' ' ' | xargs | tr ' ' '\n' | tail -1
first, tr ':' ' ' -> replace ':' with whitespace
then, trim with xargs
after that, tr ' ' '\n' -> replace remained whitespace to newline
lastly, tail -1 -> get the last string
For those that comfortable with Python, https://github.com/Russell91/pythonpy is a nice choice to solve this problem.
$ echo "a:b:c:d:e" | py -x 'x.split(":")[-1]'
From the pythonpy help: -x treat each row of stdin as x.
With that tool, it is easy to write python code that gets applied to the input.
Edit (Dec 2020):
Pythonpy is no longer online.
Here is an alternative:
$ echo "a:b:c:d:e" | python -c 'import sys; sys.stdout.write(sys.stdin.read().split(":")[-1])'
it contains more boilerplate code (i.e. sys.stdout.read/write) but requires only std libraries from python.