What is wrong with my script?

Shell Programming and Scripting
1

Dear All

The following is part of my script:

echo ${myarray[j]}
mytitle=`awk '{print substr(${myarray[j]}, 0, length(${myarray[j]})-4)}' /dev/null`

the echo ${myarray[j]} works fine;

however, I keep getting following error for the mytitle=.. part:

awk: line 1: syntax error at or near {
awk: line 1: syntax error at or near ,
awk: line 1: syntax error at or near )
awk: line 1: extra ')'

Can someone tell me what mistake did I make?

2

You have to assign an external variable to awk variable to start working on it.

No need to use /dev/null , you can print inside BEGIN block.

Also starting character in substr function is character number 1 not 0

mytitle=$( awk -v ARR="${myarray[j]}" 'BEGIN { print substr(ARR,1,length(ARR)-4) }'  )
1 Like
3

You cannot embed shell variables in an awk statement that way.
Generally

var=foo
awk -v myvar=$var '{.....}' somefile

-v [awkvariable name]=$variable

It looks like you are trying to get a substring of a variable. Some shells like bash provide that.

${string:position:length}

example:

a=123456789
len=${#a}   # length of the variable
len=$(( $len -1 4 ))
echo ${a:0:len}   # get string minus 4 characters

It is much less efficient in awk, but you can it this way (one of several) if you are not using the bash shell:

var=123456789
newvar=$(echo "$s" | awk  '{print substr($0,1,length($0)-4) }')
1 Like
4

Thank you very much!
I followed your methods; and all of them work perfectly! Thank you so much!