问是否使用grep/sed递归删除文件末尾的尾随空格？

EN

awk '{if (flag) print line; line = $0; flag = 1} END {gsub("[[:space:]]+$","",line); printf line}'

sed '/^[[:space:]]*$/{:a;$d;N;/\n[[:space:]]*$/ba}' inputfile |
    awk '{if (flag) print line; line = $0; flag = 1} END {printf line}'

#!/usr/bin/awk -f

# accumulate a run of white-space-only lines so they can be printed or discarded
/^[[:space:]]*$/ {
    accumlines = accumlines nl $0
    nl = "\n"
    accum = 1
    next
}

# print the previous line and any accumulated lines, store the current line for the next pass
{
    if (flag) print line
    if (accum) { print accumlines; accum = 0 }
    accumlines = nl = ""
    line = $0
    flag = 1
}

# print the last line without a trailing newline after removing all trailing whitespace
# the resulting output could be null (nothing rather than 0x00)
# note that we're not print the accumulated lines since they're part of the 
# trailing white-space we're trying to get rid of
END {
    gsub("[[:space:]]+$","",line)
    printf line
}

perl -e '$s = ""; while (defined($_ = getc)) { if (/\s/) { $s .= $_; } else { print $s, $_; $s = ""; } }' < infile > outfile

perl -e 'while (defined($_ = getc)) { $last = $_; } exit($last =~ /\s/);' < infile > outfile

#!/usr/bin/perl
$s = "";
while (defined($_ = getc)) {
    if (/\s/) { $s .= $_; } else { print $s, $_; $s = ""; }
}

find /top/dir -type f -exec sh -c 'mv "{}" "{}.bak" && fix.pl < "{}.bak" > "{}"' ';'

tac filename | 
awk '
    /^[[:space:]]*$/ && !seen {next} 
    /[^[:space:]]/   && !seen {gsub(/[[:space:]]+$/,""); seen=1}
    seen
' | 
tac