#!/bin/bash # echo-params.sh # Call this script with a few command-line parameters. # For example: # sh echo-params.sh first second third fourth fifth params=$# # Number of command-line parameters. param=1 # Start at first command-line param. while [ "$param" -le "$params" ] do echo -n "Command-line parameter " echo -n \$$param # Gives only the *name* of variable. # ^^^ # $1, $2, $3, etc. # Why? # \$ escapes the first "$" #+ so it echoes literally, #+ and $param dereferences "$param" . . . #+ . . . as expected. echo -n " = " eval echo \$$param # Gives the *value* of variable. # ^^^^ ^^^ # The "eval" forces the *evaluation* #+ of \$$ #+ as an indirect variable reference. (( param ++ )) # On to the next. done exit $? # ================================================= $ sh echo-params.sh first second third fourth fifth Command-line parameter $1 = first Command-line parameter $2 = second Command-line parameter $3 = third Command-line parameter $4 = fourth Command-line parameter $5 = fifth