您可以只安装GNU grep或Ack(用Perl编写,可以理解GNU grep的许多选项以及更多内容)。
如果您喜欢使用标准工具和一些脚本,那么这是一个awk脚本,它模仿GNU grep -A
和-B
options 的行为。最少测试。
#!/bin/sh
# grep-ac: a grep-like awk script
# Arguments: pattern = awk regexp to search for
# before = number of lines to print before a match
# after = number of lines to print after a match
{ "exec" "awk" "-f" "$0" "$@"; }
# The array h contains the history of lines that haven't been printed
# but are eligible for being "before" lines.
# The variable until contains the number of the last "after" line to print.
match($0, pattern) { # the current line matches
for (i in h) {
print h[i]; # print each remaining before line
delete h[i]; # delete each line as it's printed
}
until=NR+after; # record the last after line to print
}
{
if (NR<=until) print $0; # from a match to its last after line: print
else h[NR]=$0; # after that: save in history
delete h[NR-before]; # remove line too old to be a before line
}
END {exit !until} # exit status: 0 if there was a match, else 1
运行它grep-ac -vpattern=PATTERN -vbefore=NBEFORE -vafter=NAFTER
,其中PATTERN
是搜索(一个图案扩展正则表达式与几个AWK增补),并NBEFORE
和NAFTER
有线的数目之前和匹配分别(默认为0)后进行打印。例:
<input_file grep-ac -vbefore=2 -vpattern='foo *bar'
-C
切换。