Unix使用者經驗提升指令碼與技巧

#!/bin/bash
# newquota - 簡化磁碟配額查詢

flags=""
while [ $# -gt 0 ]; do
  case "$1" in
    --verbose) flags="$flags -v";;
    --quiet) flags="$flags -q";;
    *) echo "未知引數: $1"; exit 1;;
  esac
  shift
done

exec quota $flags "$@"

$ newquota --verbose
Disk quotas for user dtint (uid 24810):
Filesystem usage quota limit grace files quota limit grace
/usr 338262 614400 675840 10703 120000 126000

$ newquota --quiet

#!/bin/bash
# mysftp - 使 sftp 的使用體驗更像 ftp

/bin/echo -n "User account: "
read account
if [ -z "$account" ]; then
  exit 0
fi

if [ -z "$1" ]; then
  /bin/echo -n "Remote host: "
  read host
  if [ -z "$host" ]; then
    exit 0
  fi
else
  host=$1
fi

exec sftp -C $account@$host

$ mysftp
User account: taylor
Remote host: intuitive.com
Connecting to intuitive.com...
[email protected]'s password:
sftp> quit

$ mysftp intuitive.com
User account: taylor
Connecting to intuitive.com...
[email protected]'s password:
sftp> quit

#!/bin/bash
# cgrep：帶有上下文顯示和匹配高亮的 grep

context=0
esc=$'\033['
boldon="${esc}1m"
boldoff="${esc}22m"
sedscript="/tmp/cgrep.sed.$$"
tempout="/tmp/cgrep.$$"

function showMatches {
    matches=0
    echo "s/$pattern/${boldon}$pattern${boldoff}/g" > $sedscript
    for lineno in $(grep -n "$pattern" $1 | cut -d: -f1); do
        if [ $context -gt 0 ]; then
            prev="$(( $lineno - $context ))"
            [ $prev -lt 1 ] && prev="1"
            next="$(( $lineno + $context ))"
            if [ $matches -gt 0 ]; then
                echo "${prev}i\\" >> $sedscript
                echo "
---
-" >> $sedscript
            fi
            echo "${prev},${next}p" >> $sedscript
        else
            echo "${lineno}p" >> $sedscript
        fi
        matches="$(( $matches + 1 ))"
    done
    if [ $matches -gt 0 ]; then
        sed -n -f $sedscript $1 | uniq | more
    fi
}

trap "rm -f $tempout $sedscript" EXIT

if [ -z "$1" ]; then
    echo "用法: $0 [-c X] 模式 {檔案名}" >&2
    exit 0
fi

if [ "$1" = "-c" ]; then
    context="$2"
    shift; shift
elif [[ "$1" == "-c"* ]]; then
    context="${1#-c}"
    shift
fi

pattern="$1"; shift

if [ $# -gt 0 ]; then
    for filename; do
        echo "
---
-- $filename 
---
--"
        showMatches "$filename"
    done
else
    cat > "$tempout"
    showMatches "$tempout"
fi

exit 0

#!/bin/bash
# zcat, zmore, 和 zgrep：允許使用者透明地處理壓縮檔案

Z="compress"; unZ="uncompress"; Zlist=""
gz="gzip"; ungz="gunzip"; gzlist=""
bz="bzip2"; unbz="bunzip2"; bzlist=""

for arg; do
    if [ -f "$arg" ]; then
        case "$arg" in
            *.Z) $unZ "$arg"; arg="${arg%.Z}"; Zlist="$Zlist \"$arg\"";;
            *.gz) $ungz "$arg"; arg="${arg%.gz}"; gzlist="$gzlist \"$arg\"";;
            *.bz2) $unbz "$arg"; arg="${arg%.bz2}"; bzlist="$bzlist \"$arg\"";;
        esac
    fi
    newargs="$newargs \"$arg\""
done

case "$(basename "$0")" in
    *zcat*) eval cat $newargs;;
    *zmore*) eval more $newargs;;
    *zgrep*) eval grep $newargs;;
    *) echo "$0: 未知的基礎名稱。無法繼續。" >&2; exit 1;;
esac

if [ -n "$Zlist" ]; then eval $Z $Zlist; fi
if [ -n "$gzlist" ]; then eval $gz $gzlist; fi
if [ -n "$bzlist" ]; then eval $bz $bzlist; fi

exit 0

#!/bin/bash
# bestcompress--Given a file, tries compressing it with all the available
# compression tools and keeps the compressed file that's smallest,
# reporting the result to the user. If -a isn't specified, bestcompress
# skips compressed files in the input stream.

Z="compress" gz="gzip" bz="bzip2"
Zout="/tmp/bestcompress.$$.Z"
gzout="/tmp/bestcompress.$$.gz"
bzout="/tmp/bestcompress.$$.bz2"
skipcompressed=1

if [ "$1" = "-a" ] ; then
  skipcompressed=0 ; shift
fi

if [ $# -eq 0 ]; then
  echo "Usage: $0 [-a] file or files to optimally compress" >&2
  exit 1
fi

trap "/bin/rm -f $Zout $gzout $bzout" EXIT

for name in "$@"
do
  if [ ! -f "$name" ] ; then
    echo "$0: file $name not found. Skipped." >&2
    continue
  fi

  if [ "$(echo $name | egrep '(\.Z$|\.gz$|\.bz2$)')" != "" ] ; then
    if [ $skipcompressed -eq 1 ] ; then
      echo "Skipped file ${name}: It's already compressed."
      continue
    else
      echo "Warning: Trying to double-compress $name"
    fi
  fi

  # 同時使用多種壓縮工具進行壓縮
  $Z < "$name" > $Zout &
  $gz < "$name" > $gzout &
  $bz < "$name" > $bzout &
  wait # 等待所有壓縮作業完成

  # 找出最小的壓縮檔案
  smallest="$(ls -l "$name" $Zout $gzout $bzout | \
    awk '{print $5"="NR}' | sort -n | cut -d= -f2 | head -1)"

  case "$smallest" in
    1 ) echo "No space savings by compressing $name. Left as is."
      ;;
    2 ) echo "Best compression is with compress. File renamed ${name}.Z"
      mv $Zout "${name}.Z" ; rm -f "$name"
      ;;
    3 ) echo "Best compression is with gzip. File renamed ${name}.gz"
      mv $gzout "${name}.gz" ; rm -f "$name"
      ;;
    4 ) echo "Best compression is with bzip2. File renamed ${name}.bz2"
      mv $bzout "${name}.bz2" ; rm -f "$name"
      ;;
  esac
done

exit 0

$ ls -l alice.txt
-rw-r--r-- 1 taylor staff 154872 Dec 4 2002 alice.txt

$ bestcompress alice.txt
Best compression is with compress. File renamed alice.txt.Z

$ ls -l alice.txt.Z
-rw-r--r-- 1 taylor wheel 66287 Jul 7 17:31 alice.txt.Z