为什么不能使用以下bash代码？
for i in $( echo "emmbbmmaaddsb" | split -t "mm" )
do
echo "$i"
done
预期产量：
e bb aaddsb
由于您需要换行符,因此您只需使用换行符替换字符串中mm的所有实例即可.在纯粹的原生bash中：
in='emmbbmmaaddsb'
sep='mm'
printf '%s\n' "${in//$sep/$'\n'}"
如果你想在更长的输入流上做这样的替换,你可能最好使用awk,因为bash的内置字符串操作不能很好地扩展到超过几千字节的内容. BashFAQ #21中给出的gsub_literal shell函数(后端到awk)适用：
# Taken from http://mywiki.wooledge.org/BashFAQ/021
# usage: gsub_literal STR REP
# replaces all instances of STR with REP. reads from stdin and writes to stdout.
gsub_literal() {
# STR cannot be empty
[[ $1 ]] || return
# string manip needed to escape '\'s,so awk doesn't expand '\n' and such
awk -v str="${1//\\/\\\\}" -v rep="${2//\\/\\\\}" '
# get the length of the search string
BEGIN {
len = length(str);
}
{
# empty the output string
out = "";
# continue looping while the search string is in the line
while (i = index($0,str)) {
# append everything up to the search string,and the replacement string
out = out substr($0,1,i-1) rep;
# remove everything up to and including the first instance of the
# search string from the line
$0 = substr($0,i + len);
}
# append whatever is left
out = out $0;
print out;
}
'
}
……在这种情况下,用作：
gsub_literal "mm" $'\n' <your-input-file.txt >your-output-file.txt
