Call user defined function from awk

UNIX for Beginners Q & A
1

My requirement is to call function ("fun1") from awk, and print its returned value along with $0.

fun1()
{
   t=$1
   printf "%02d\n", $t % 60;
}

echo "Hi There 23" | awk '{print $0; system(fun1 $3)}'

Any suggestions what to be modified in above code to achieve requirement..

2

Why not use awks' own printf? - Printf Examples (The GNU Awk User�s Guide)

3

We have existing function ("fun1") with complex calculations. For the sake of simplicity, i havn't mentioned here.
As part of reusability, we are asked to call this function wherever needed.

4

Your chances are low. While the function definition somehow survives - if export ed! - and makes it into awk 's environment under a modified name, like

BASH_FUNC_fun1%% = () {  t=$1;
 printf "%02d\n" $(($t % 60))
}

, the system command creates another process running /bin/sh which seems to lose the exported function definitions.

5

You can process your test with PHP or Python, for example, and then call your awk (or any external) function from there.

6

Hi JSKOBS...

Not quite exactly what you are looking for but a little bit of lateral thinking creates this.

#!/bin/sh
# awk_shell.sh

: > /tmp/myfunc
chmod 755 /tmp/myfunc

cat << "EOF" > /tmp/myfunc
#!/bin/sh
t=${1}
printf "%02d\n" "$(( t % 60 ))"
EOF

result=$( echo "Hi There 123" | awk '{ print $0; system("/tmp/myfunc "$3)}' )

echo "${result}"

Results; OSX 10.14.6, default bash terminal...

Last login: Wed Nov  6 20:47:08 on ttys000
AMIGA:amiga~> cd Desktop/Code/Shell
AMIGA:amiga~/Desktop/Code/Shell> chmod 755 awk_shell.sh
AMIGA:amiga~/Desktop/Code/Shell> ./awk_shell.sh
Hi There 123
03
AMIGA:amiga~/Desktop/Code/Shell> _
1 Like