I have a string let's say
k=CHECK_${SOMETHING}_CUSTOM_executable.acs
Now I want to fetch only CUSTOM_executable from the above string. This is what I have tried so far in Unix
echo $k|awk -F '_' '{print $2}'
Can you explain how can i do this
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5 Answers
Try this :
$ echo "$k"
CHECK_111_CUSTOM_executable.acs
code:
echo "$k" | awk 'BEGIN{FS=OFS="_"}{sub(/.acs/, "");print $3, $4}'
2 Comments
ramaswamy
Hi Suppose my SOMETHING is 111_111 ? Then how can i handle this?
Gilles Quénot
Then you have to use $4, $5
Assume the variable ${SOMETHING} has the value SOMETHING just for simplicity.
The following assignment, therefore,
k=CHECK_${SOMETHING}_CUSTOM_executable.acs
sets the value of k to CHECK_SOMETHING_CUSTOM_executable.acs.
When split into fields on _ by awk -F '_' (note the single quotes aren't necessary here).
You get the following fields:
$ echo "$k" | awk -F _ '{for (i=0; i<=NF; i++) {print i"="$i}}'
0=CHECK_SOMETHING_CUSTOM_executable.acs
1=CHECK
2=SOMETHING
3=CUSTOM
4=executable.acs
So to get the output you want simply use
echo "$k" | awk -F _ -v OFS=_ '{print $3,$4}'
Comments
Suppose if SOMETHING variable is having 111_222_333 (or) 111_222_333_444,
Use this:
$ k=CHECK_${SOMETHING}_CUSTOM_executable.acs
$ echo $k | awk 'BEGIN{FS=OFS="_"}{ print $(NF-1),$NF }'
(Or)
echo $k | awk -F_ '{ print $(NF-1), $NF }' OFS=_
Explanation :
NF - The number of fields in the current input record.
Comments
Try this simple awk:
awk -F[._] '{print $3"_"$4}' <<<"$k"
CUSTOM_executable
The -F[._] defines both dot and underline as field separator. Then awk prints the filed number 3 and 4 from $k as input.
If the k contains k='CHECK_${111_111}_CUSTOM_executable.acs', then use filed with numbers $4 and $5:
awk -F[._] '{print $4"_"$5}' <<<"$k"
CHECK_${111_111}_CUSTOM_executable.acs
| $1| |$2 | |$3| | $4 | | $5 | |$6|
Comments
You do not need to use awk, it can be done in bash easily. I assume that $SOMETHING does not contains _ characters (also CUSTOM and executable part is just some text, they also not contains _). Then:
k=CHECK_${SOMETHING}_CUSTOM_executable.acs
l=${k#*_}; l=${l#*_}; l=${l%.*};
This cuts anything from the beginning to the 2nd _ char, and chomps off anything after the last . char. Result is put into the l env.var.
If $SOMETHING may contain _ then a little bit work has to be done (I assume the CUSTOM and executable part does not contain _):
k=CHECK_${SOMETHING}_CUSTOM_executable.acs
l=${k%_*}; l=${l%_*}; l=${k#${l}_*}; l=${l%.*};
This chomps off everything after the last but one _ character, the cuts the result off from the original string. The last statement chomps the extension off. The result is in l env.var.
Or it can be done using regex:
[[ $k =~ ([^_]+_[^_]+)\.[^.]+$ ]] && l=${BASH_REMATCH[1]}
This matches any string containing two words separated by _ and finished with .<extension>. The extension part is chomped off and result is in l env.var.
I hope this helps!
