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#!/bin/bash
# substring-extraction.sh
String=23skidoo1
# 012345678 Bash
# 123456789 awk
# Note different string indexing system:
# Bash numbers first character of string as 0.
# Awk numbers first character of string as 1.
echo ${String:2:4} # position 3 (0-1-2), 4 characters long
# skid
# The awk equivalent of ${string:pos:length} is substr(string,pos,length).
echo | awk '
{ print substr("'"${String}"'",3,4) # skid
}
'
# Piping an empty "echo" to awk gives it dummy input,
#+ and thus makes it unnecessary to supply a filename.
echo "----"
# And likewise:
echo | awk '
{ print index("'"${String}"'", "skid") # 3
} # (skid starts at position 3)
' # The awk equivalent of "expr index" ...
exit 0
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