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replaceend
Unlike Bourne Again Shell (bash), POSIX shell does not have a native find/replace function for replacing a pattern at the end of a given string with another. Below is an implementation written in native POSIX shell that is:
- Faster than piping to
awk,sed,perl,python,ruby, or other langauge - Compatible with
bashand all other POSIX-compliant shells - Optimized to use
${parameter/%pattern[/string]}whenbashis detected
1 #!/bin/sh
2 if [ "$BASH_VERSION" ]; then
3 replaceend() # $var_to_get $find $replace [$var_to_set]
4 {
5 eval ${4:-$1}=\"\${$1/%\$2${3:+/\$3}}\"
6 }
7 else
8 # NB: On FreeBSD, sh(1) runs this faster than bash(1) runs the above
9 replaceend() # $var_to_get $find $replace [$var_to_set]
10 {
11 eval local __string=\"\$$1\" || return
12 case "$__string" in *$2)
13 __string="${__string%$2}$3"
14 esac
15 eval ${4:-$1}=\"\$__string\"
16 }
17 fi
18 eval echo \"before=[\$$1]\"
19 replaceend "$@"
20 eval echo \" after=[\$${4:-$1}]\"
Last modified 3yr ago