How can I split a shell command over multiple lines when using an IF statement

Question

How can I split a command over multiple lines in the shell  when the command is part of an if statement   This works    if   fab --fabfile  deploy fabfile py --forward-agent --disable-known-hosts deploy  target  then rc 1                                                                        fi   This doesn t work      does not work  if   fab --fabfile  deploy fabfile py      --forward-agent     --disable-known-hosts deploy  target  then      rc 1 fi   Instead of the whole command executing  I get     script sh  line 73  --forward-agent  command not found   More importantly  what is missing from my understanding of Bash that will help me understand this and similar issues in the future

User · Answer

For Windows WSL Cygwin etc users   Make sure that your line endings are standard Unix line feeds  i e   n  LF  only   Using Windows line endings  r n  CRLF  line endings will break the command line break     This is because having   at the end of a line with Windows line ending translates to    r  n  As Mark correctly explains above      The line-continuation will fail if you have whitespace after the backslash and before the newline    This includes not just space    or tabs   t  but also the carriage return   r

User · Answer

The line-continuation will fail if you have whitespace  spaces or tab characters 1   after the backslash and before the newline  With no such whitespace  your example works fine for me    cat test sh if   fab --fabfile  deploy fabfile py      --forward-agent      --disable-known-hosts deploy  target  then      echo failed else      echo succeeded fi    alias fab true      test sh succeeded   alias fab false      test sh failed  Some detail promoted from the comments  the line-continuation backslash in the shell is not really a special case  it is simply an instance of the general rule that a backslash  quot quotes quot  the immediately-following character  preventing any special treatment it would normally be subject to  In this case  the next character is a newline  and the special treatment being prevented is terminating the command  Normally  a quoted character winds up included literally in the command  a backslashed newline is instead deleted entirely  But otherwise  the mechanism is the same  Most importantly  the backslash only quotes the immediately-following character  if that character is a space or tab  you just get a literal space or tab  and any subsequent newline remains unquoted   1  or carriage returns  for that matter  as Czechnology points out  Bash does not get along with Windows-formatted text files  not even in WSL  Or Cygwin  but at least their Bash port has added a set -o igncr option that you can set to make it carriage-return-tolerant

[syntax] How can I split a shell command over multiple lines when using an IF statement?

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