1663
Comment: expr length is no better. WA needed for both.
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1495
remove broken code for simplification. exit only needed in old awk (which doesn't support ARGV)
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Deletions are marked like this. | Additions are marked like this. |
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${#varname} | "${#varname}" |
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# Bourne awk -v x="$varname" 'BEGIN {print length(x)}' }}} Though that one will fail for values of $varname that contain backslash characters, so you may prefer: {{{ |
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awk 'BEGIN {print length(ARGV[1]);exit}' "$varname" | awk 'BEGIN {print length(ARGV[1])}' "$varname" |
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${#arrayname[@]} | "${#arrayname[@]}" |
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Returns the number of elements in an array. | Expands to the number of elements in an array. |
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${#arrayname[i]} | "${#arrayname[i]}" |
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Returns the length of the array's element i. | Expands to the length of the array's element i. |
Is there a function to return the length of a string?
The fastest way, not requiring external programs (but not usable in Bourne shells):
# POSIX "${#varname}"
(note that with bash 3 and above, that's the number of characters, not bytes, which is a significant differences in multi-byte locales. Behaviour of other shells in that regard vary).
or for Bourne shells:
# Bourne expr "x$varname" : '.*' - 1
(expr prints the number of characters or bytes matching the pattern .*, which is the length of the string (in bytes for GNU expr). The x is necessary to avoid problems with $varname values that are expr operators)
or:
# Bourne, with GNU expr(1) expr length "x$varname" - 1
(BSD/GNU expr only)
This second version is not specified in POSIX, so is not portable across all platforms.
A portable way is:
expr \( "X$varname" : ".*" \) - 1
One may also use awk:
# Bourne with POSIX awk awk 'BEGIN {print length(ARGV[1])}' "$varname"
(there, whether the length is expressed in bytes or characters depends on the implementation (for instance, it's characters for GNU awk, but bytes for mawk).
Similar needs:
# Korn/Bash "${#arrayname[@]}"
Expands to the number of elements in an array.
# Korn/Bash "${#arrayname[i]}"
Expands to the length of the array's element i.