I created shell script, that logs into FTP server and renames some directories. I put FTP commands in multiline string like so
# !/bin/sh ftp -inv $HOST << EOF user $USER $PASSWORD $COMMANDS bye EOF
$COMMANDS contains commands separated by new line. This approach works, when I construct command like so
NL=$'\n' COMMANDS="command one$NL" COMMANDS+="command two$NL" COMMANDS+="command three"
I firstly tried populate
$COMMANDS with function
printf, but even after several trials, I was unsuccessful. The expression
COMMANDS="$(printf "%s\n" "command one" "command two" "command three")"
evaluated to string with blank spaces between commands and when used in script as FTP command, it was processed as single line.
I tried replace
\r which results in variable
$COMMANDS not beeing populated with any string.
Can someone more educated please explain to me, whats the problem with
printf function here?
I've manage how to achieve my goal via rsync, so the FTP approach I've abandoned, but I'm still curious why this happens.
Problem is with storing
printf in variable. I made test script:
echo "==== printf directly" printf "%s\n" "foo" "bar" "baz" echo "==== stored in variable" VAR_1=$(printf "%s\n" "foo" "bar" "baz") echo $VAR_1
==== printf directly foo bar baz ==== stored in variable foo bar baz
IFS=$'\n' does not help.
I can get multiline from variable if I wrap it in double qotes
but I'm unable to get the same result if used inside heredoc
echo `cat <<EOF $VAR_1 "$VAR_1" EOF`
I get output
foo bar baz "foo bar baz"
note: there is even no newline between the two variable outputs in heredoc, which is also strange to me.