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Full Discussion: If else with one variable
Top Forums Shell Programming and Scripting If else with one variable Post 302918396 by Don Cragun on Tuesday 23rd of September 2014 06:05:22 AM
Old 09-23-2014
Quote:
Originally Posted by sea
Could be shorter..
Code:
read -p "Who are you: " line
[ -z $line ] && line=kim
echo "Hi $line"


Hope this helps
Although the test [ -z $line ] will work as long as no more than one word was typed in; it isn't doing what most people expect.

If an empty line is entered, it will expand to [ -z ] which will yield TRUE because "-z" is not an empty string (not because $line expands to an empty string).

If a single word is entered (and it does not contain any pattern matching characters that would match more than one file in the current directory), then it will expand to [ -z word ] which will evaluate to TRUE as expected.

If more than one word is entered or any pattern matching characters in a single word expand to a list of more than one filename, you will either get a syntax error or some random result depending on what the 1st word is and, if there are more than two words (after pattern matching), it will also depend on the subsequent words.

To use this form reliably, the line:
Code:
[ -z $line ] && line=kim

should be changed to:
Code:
[ -z "$line" ] && line=kim

 

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uuencode(4)						     Kernel Interfaces Manual						       uuencode(4)

NAME
uuencode - format of an encoded uuencode file DESCRIPTION
Files output by consist of a header line followed by a number of body lines, and a trailer line. The command ignores any lines preceding the header or following the trailer (see uuencode(1)). Lines preceding a header must not look like a header. The header line consists of the word followed by a space, a mode (in octal), another space, and a string which specifies the name of the remote file. The body consists of a number of lines, each containing 62 or fewer characters (including trailing new-line). These lines consist of a character count, followed by encoded characters, followed by a newline. The character count is a single printing character, which represents an integer. This integer is the number of bytes in the rest of the line, and always ranges from 0 to 63. The byte count can be determined by subtracting the equivalent octal value of an ASCII space charac- ter (octal 40) from the character. Groups of 3 bytes are stored in 4 characters, 6 bits per character. All are offset by a space to make the characters printable. The last line may be shorter than the normal 45 bytes. If the size is not a multiple of 3, this fact can be determined by the value of the count on the last line. Extra meaningless data will be included, if necessary, to make the character count a multiple of 4. The body is terminated by a line with a count of zero. This line consists of one ASCII space. The trailer line consists of the word on a line by itself. SEE ALSO
mail(1), uuencode(1), uucp(1). uuencode(4)
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