I am writing a shell script for linux which takes argument as port no. inside file following is a line which needs to be updated:
define('NO_OF_PORTS',10);
I need to replace that 10 by the argument passed. But this should be dynamic, like next time I pass new port no it must get updated.
Using sed:
s="define('NO_OF_PORTS',10);"
n=25
sed "s/\('NO_OF_PORTS',\)[0-9]*/\1$n/" <<< "$s"
define('NO_OF_PORTS',25);
To change inline in the file use:
sed -i.bak "s/\('NO_OF_PORTS',\)[0-9]*/\1$n/" file
s='define('NO_OF_PORTS',10);' is not equivalent to s='define('\''NO_OF_PORTS'\'',10);' (or s="define('NO_OF_PORTS',10);"), while I think here it shall be the later ones but not the one you're using.
You can use sed in the script to edit the file
sed -i s/NO_OF_PORTS\',[0-9]*/NO_OF_PORTS\',$1/ $2
1.txt has
define('NO_OF_PORTS',19)
shell script
#!/bin/sh
echo $1
sed -i -r '/NO_OF_PORTS/ s/'[0-9]+'/'$1'/g' 1.txt
run
linux:/home/test # ./replace_port.sh 78
linux:/home/test # cat 1.txt
define('NO_OF_PORTS',78)
