我正在使用此脚本生成系统上包含手册页的可用命令列表。使用time
运行此操作会在我的计算机上显示平均约49秒。
#!/usr/local/bin/bash
for x in $(for f in $(compgen -c); do which $f; done | sort -u); do
dir=$(dirname $x)
cmd=$(basename $x)
if [[ ! $(man --path "$cmd" 2>&1) =~ 'No manual entry' ]]; then
printf '%b\n' "${dir}:\n${cmd}"
fi
done | awk '!x[$0]++'
有没有办法对此进行优化以获得更快的结果?
这是我当前输出的一小部分样本。目标是按目录对命令进行分组。这将在以后被送入数组。
/bin: # directories generated by $dir
[ # commands generated by $cmd (compgen output)
cat
chmod
cp
csh
date
答案 0 :(得分:0)
在这里完全无视内置插件。无论如何,那是which
的作用。脚本未经过彻底测试。
#!/bin/bash
shopt -s nullglob # need this for "empty" checks below
MANPATH=${MANPATH:-/usr/share/man:/usr/local/share/man}
IFS=: # chunk up PATH and MANPATH, both colon-deliminated
# just look at the directory!
has_man_p() {
local needle=$1 manp manpp result=()
for manp in $MANPATH; do
# man? should match man0..man9 and a bunch of single-char things
# do we need 'man?*' for longer suffixes here?
for manpp in "$manp"/man?; do
# assumption made for filename formats. section not checked.
result=("$manpp/$needle".*)
if (( ${#result[@]} > 0 )); then
return 0
fi
done
done
return 1
}
unset seen
declare -A seen # for deduplication
for p in $PATH; do
printf '%b:\n' "$p" # print the path first
for exe in "$p"/*; do
cmd=${exe##*/} # the sloppy basename
if [[ ! -x $exe || ${seen[$cmd]} == 1 ]]; then
continue
fi
seen["$cmd"]=1
if has_man_p "$cmd"; then
printf '%b\n' "$cmd"
fi
done
done
使用截断的PATH在Cygwin上的时间(Windows的完整版本对原始版本有太多错失):
$ export PATH=/usr/local/bin:/usr/bin
$ time (sh ./opti.sh &>/dev/null)
real 0m3.577s
user 0m0.843s
sys 0m2.671s
$ time (sh ./orig.sh &>/dev/null)
real 2m10.662s
user 0m20.138s
sys 1m5.728s
(两个版本的警告:Cygwin /usr/bin
中的大多数内容都带有.exe
扩展名