Shell tips
Короткие заметки по shell-программированию
Передать переменные в SED и AWK
$ echo "unix scripting" unix scripting
In SED:
This is a general substitution. I am trying to replace "unix" with "BASH", so "unix scripting" will become "BASH scripting"
$ echo "unix scripting" | sed 's/unix/BASH/' BASH scripting
Suppose, the text "BASH" is assigned to a variable called "var", now if I try to replace "unix" with "$var" in sed single quote notation, its not going to work as SED can't expand external variable in single quotes.
$ var="BASH"; echo "unix scripting" | sed 's/unix/$var/' $var scripting
Try the same above with double quotes, this will work.
$ var="BASH"; echo "unix scripting" | sed "s/unix/$var/" BASH scripting
In AWK
General substitution of "unix" with "BASH", will work. "unix scripting" will become "BASH scripting"
$ echo "unix scripting" | awk '{gsub(/unix/,"BASH")}; 1'
BASH scripting
"BASH" is assigned in variable "var". So the following substitution is not going to work.
$ var="BASH"; echo "unix scripting" | awk '{gsub(/unix/,"$var")}; 1'
$var scripting
Method1: See the "'" (double quote-single quote-double quote) before and after the variable var.
$ var="BASH"; echo "unix scripting" | awk '{gsub(/unix/,"'"$var"'")}; 1'
BASH scripting
Method2: Use awk -v flag this way.
$ var="BASH"; echo "unix scripting" | awk -v v="$var" '{sub(/unix/,v)}1'
BASH scripting
Округление
04:45:14-root@wiki:~$ printf "%0.f\n" 4.51 5
while БЕЗ subshell
Способ Ворона
exec 3<$TMP_FILE1
# 0 -stdin ... 2 stderr, 3 - first free descriptor
while read -u 3 NUMBER TYPE
do
echo NUMBER=$NUMBER TYPE=$TYPE
done
Считываени нескольких переменных
Пример 1:
cat /tmp/service-perfdata | grep ttiweb | grep APACHE_HTTPS | grep -v "CRITICAL" | awk '{ print $2" " $16}' | tail -5000 | while read DATE TIMEOUT
do
DATE1=`date -d @$DATE`
TIMEOUT1=`echo $TIMEOUT |awk -F"[" '{ print $2 }'`
echo $DATE1"|"$TIMEOUT1
done
Но для чтения инужно явно делать саб-шелл Пример 2:
for FILE in `ls -1 *.log`
do
echo $FILE | awk -F"-" '{ print $1" "$2" "$3" "$5 }' | ( read YYYY MM DD TIME
# Subshell fore read!
# echo $YYYY $MM $DD
TIME=`echo $TIME | awk -F"__" '{print $1}'`
hh=`echo $TIME | cut -b 1-2`
mm=`echo $TIME | cut -b 3-4`
D=`date +%s --date="${YYYY}/$MM/$DD $hh:$mm"`
TMPFILE=`mktemp`
cat $FILE | grep -v "USER" | head -10 > $TMPFILE
)
done
if-els
коротко можно желать например, так
function export_data
{
(
$JAVA_HOME/bin/java -Xbootclasspath/a:$CLASSPATH -jar $BIARENGINE $CONFIG_FILE && (
if test -f $BOXI_EXPORT_FILE
then
echo "${DATE_FOR_LOG_FILES}:BOXI Export=SUCCEEDED" | tee -a $SYNC_STATUS_FILE
clear_tmp
exit 0
else
echo "${DATE_FOR_LOG_FILES}:BOXI Export=FAILED" | tee -a $SYNC_STATUS_FILE
fi )
) || ( echo "${DATE_FOR_LOG_FILES}:BOXI Export=FAILED" | tee -a $SYNC_STATUS_FILE )
}
find
For example:
find . -mtime 0 # find files modified between now and 1 day ago
# (i.e., within the past 24 hours)
find . -mtime -1 # find files modified less than 1 day ago
# (i.e., within the past 24 hours, as before)
find . -mtime 1 # find files modified between 24 and 48 hours ago
find . -mtime +1 # find files modified more than 48 hours ago
find . -mmin +5 -mmin -10 # find files modified between
# 6 and 9 minutes ago
Using the "-printf" action instead of the default "-print" is useful to control the output format better than you can with ls or dir. You can use find with -printf to produce output that can easily be parsed by other utilities or imported into spreadsheets or databases. See the man page for the dozens of possibilities with the -printf action. (In fact find with -printf is more versatile than ls and is the preferred tool for forensic examiners even on Windows systems, to list file information.) For example the following displays non-hidden (no leading dot) files in the current directory only (no subdirectories), with an custom output format:
find . -maxdepth 1 -name '[!.]*' -printf 'Name: %16f Size: %6s\n'
"-maxdepth" is a Gnu extension. On a modern, POSIX version of find you could use this:
find . -path './*' -prune ...
On any version of find you can use this more complex (but portable) code:
find . ! -name . -prune ...
which says to "prune" (don't descend into) any directories except ".".
Note that "-maxdepth 1" will include "." unless you also specify "-mindepth 1". A portable way to include "." is:
find . \( -name . -o -prune \) ...
[This information posted by Stephane Chazelas, on 3/10/09 in newsgroup comp.unix.shell.]
As a system administrator you can use find to locate suspicious files (e.g., world writable files, files with no valid owner and/or group, SetUID files, files with unusual permissions, sizes, names, or dates). Here's a final more complex example (which I saved as a shell script):
find / -noleaf -wholename '/proc' -prune \
-o -wholename '/sys' -prune \
-o -wholename '/dev' -prune \
-o -wholename '/windows-C-Drive' -prune \
-o -perm -2 ! -type l ! -type s \
! \( -type d -perm -1000 \) -print
This says to seach the whole system, skipping the directories /proc, /sys, /dev, and /windows-C-Drive (presumably a Windows partition on a dual-booted computer). The Gnu -noleaf option tells find not to assume all remaining mounted filesystems are Unix file systems (you might have a mounted CD for instance). The "-o" is the Boolean OR operator, and "!" is the Boolean NOT operator (applies to the following criteria).
So these criteria say to locate files that are world writable ("-perm -2", same as "-o=w") and NOT symlinks ("! -type l") and NOT sockets ("! -type s") and NOT directories with the sticky (or text) bit set ("! \( -type d -perm -1000 \)"). (Symlinks, sockets and directories with the sticky bit set are often world-writable and generally not suspicious.)
A common request is a way to find all the hard links to some file. Using "ls -li file" will tell you how many hard links the file has, and the inode number. You can locate all pathnames to this file with:
find mount-point -xdev -inum inode-number
Since hard links are restricted to a single filesystem, you need to search that whole filesystem so you start the search at the filesystem's mount point. (This is likely to be either "/home" or "/" for files in your home directory.) The "-xdev" options tells find to not search any other filesystems.
(While most Unix and all Linux systems have a find command that supports the "-inum" criterion, this isn't POSIX standard. Older Unix systems provided the "ncheck" utility instead that could be used for this.)
Solaris-specific
У find на солярисе нет ключа -mmin иногда можно обойтись ключем
find $LOG_DIR/j2ee/FAM/ -newer /tmp/1/logs-fam-indusora-Fri-Aug-20.tar.bz2
