KitzKikz: ShellTricks
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These are some unix shell (bash/ksh/tcsh/...) tricks I've collected. I'm placing them here because, typically I'm away from my personal machine when I most need one. ---- __Last Workday/Weekday of the Month__ (see ["here" http://forums.macosxhints.com/showpost.php?s=a67d9453f9c5581c62107fa4c33ef19b&p=505614&postcount=17]) <code> cal | awk '{print $2,$3,$4,$5,$6}' | tr -s '[:blank:]' '\n' | tail -1 </code> ---- __Yesterday in Perl__ <code> perl -e '@T=localtime(time-86400);printf("%2d/%2d/%4d\n",$T[4]+1,$T[3],$T[5]+1900)' perl -e 'use POSIX;print POSIX::strftime("%m/%d/%Y\n",localtime(time-86400))' </code> ---- __Fast Process Search (fps)__ - I'm constantly checking to see if a certain program or process is running. This helps reduce the typing and the clutter. <code> function fps { (( $# )) && ps -aux | sed -n "1p;/___fps___/d;/$1/p" || echo "Usage: fps <search string>" } </code> Modified for use with multiple words in any order: <code> function fps { typeset x y for x in $@; do y="$y/$x/!d;"; done ps -ef | sed -n "1p;/___fps___/d;${y}p" } </code> ---- __List All Available Man Pages__: <code> man --path | perl -pe 's/:/\n/g' | xargs -J% -n1 find % -type f | xargs basename | sort -u </code> ---- __Dos2Unix Line Ending Conversion__: <code> perl -pi -e 's/\r\n/\n/;' filename ... </code> ---- __Subtract Files:__ Output all lines in FileA not also in FileB <code> sort FileA | uniq | sort - FileB FileB | uniq -u </code> | FileA | FileB | Result | |{ valign=top } a%%%a%%%b%%%c%%%d%%%e | c%%%d%%%e%%%f%%%g | a%%%b | If you know that FileA contains unique lines only, then this simplifies to: <code> sort FileA FileB FileB | uniq -u </code> ---- __Programmatically Edit Crontab__ <code> # Disable all cron jobs EDITOR='perl -pi -e s/^/#off#/' crontab -e; crontab -l # Enable all cron jobs EDITOR='perl -pi -e s/^#off#//' crontab -e; crontab -l </code> ---- __Find the location of a Perl Module__ <code> perl -MXML::Parser -le 'print for grep /Parser/, values %INC' </code> ---- __Preserve File Modification Time__ <code> x=filename /usr/bin/perl -e ' my ($ss,$mm,$hh,$DD,$MM,$YY)=localtime((stat($ARGV[0]))[9]); printf "%04d%02d%02d%02d%02d.%02d",$YY+1900,$MM+1,$DD,$hh,$mm,$ss,$ARGV[0]; ' "$x" | read t Modify the file /bin/touch -t $t "$x" </code> Entirely within perl: <code> $filename = $ARGV[0]; ($atime,$mtime) = (stat($filename))[8,9]; open(FP,">>$filename"); print FP "Add a line of text.\n"; close(FP); utime($atime,$mtime,$filename); </code> ---- __Oldest File in Directory Tree__ <code> pwd; find . -type f -print | { read OLDEST while read FILE; do [[ $OLDEST -nt $FILE ]] && OLDEST=$FILE done ls -l $OLDEST } </code> |
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