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Commands by arcege from sorted by
Terminal - Commands by arcege - 21 results
tail -f file | awk '{now=strftime("%F %T%z\t");sub(/^/, now);print}'
dd if=/dev/zero of=/fs/to/fill/dummy00 bs=8192 count=$(df --block-size=8192 / | awk 'NR!=1 {print $4-100}')
2009-12-03 15:20:18
User: arcege
Functions: awk dd df
Tags: dd df
-3

For disk space constraint testing. Leaves a little space available for creating temp files, etc. Easily free up the used disk space again by deleting the dummy00 file. Can tailor the testing by building smaller 'blocks' to suit the needs of the testing.

WARNING: do not do this to the '/' (root) filesystem unless you know what you are doing... on some systems it could crash the OS.

read -sn 1 -p 'Press any key to continue...';echo
TIMEUNIT=$(awk '/timescale/{print NR}' a)
awk 'BEGIN{dir=DIR?DIR:ENVIRON["PWD"];l=split(dir,parts,"/");last="";for(i=1;i<l+1;i++){d=last"/"parts[i];gsub("//","/",d);system("ls -ld \""d"\"");last=d}}'
2009-10-22 16:28:07
User: arcege
Functions: awk
-1

Handled all within awk. Takes the value from $PWD and constructs directory structures and runs commands against them. The gsub() call is not necessary, but added for better visibility.

If a variable DIR is given on the awk command-line, then that directory is used instead:

awk -vDIR=$HOME/.ssh 'BEGIN{dir=DIR?...}'
sed -ne '/^Package: \(.*\)/{s//\1/;h;};/^Installed-Size: \(.*\)/{s//\1/;G;s/\n/ /;p;}' /var/lib/dpkg/status | sort -rn
2009-10-19 19:01:17
User: arcege
Functions: sed sort
2

Use the hold space to preserve lines until data is needed.

not () { "$@" && return 1 || return 0; }
2009-09-23 01:09:53
User: arcege
Functions: return
Tags: shell
-4

Useful in while and if statements

if not grep string filename; then echo string not found; exit 1; fi
echo 127.0.0.1 | egrep -e '^(([01]?[0-9]{1,2}|2[0-4][0-9]|25[0-4])\.){3}([01]?[0-9]{1,2}|2[0-4][0-9]|25[0-4])$'
2009-09-17 17:40:48
User: arcege
Functions: echo egrep
-1

Handles everything except octets with 255. Ran through ip generator with variable octet lengths.

budir=/tmp/bu.$$;for name in repMainPath/*/format;do dir=${name%/format};bufil=dumpPath/${dir##*/};svnadmin hotcopy --clean-logs $dir $budir;svnadmin dump --delta $budir>$bufil;rm -rf $budir;done
2009-09-16 01:34:48
User: arcege
Functions: dump
Tags: bash svn
2

Use of hotcopy for safety/stability of the backups.

rm -rf [a-bd-zA-Z0-9]* c[b-zA-Z0-9]*
2009-09-15 14:22:56
User: arcege
Functions: rm
Tags: shell rm
1

Remove everything in current directory except files starting with "ca".

: ${VAR:?unset variable}
2009-09-14 19:41:01
User: arcege
Tags: shell
-1

Works in all shells. Does not require a test. Handles like an assertion.

for L in `echo :$PATH | tr : '\n'`; do F=${L:-"."}/fileName; if [ -f ${F} -o -h ${F} ]; then echo ${F}; break; fi; done
2009-09-11 16:14:36
User: arcege
Functions: echo tr
-1

Searches in order of the directories of $PATH. Stops after finding the entry; looks for only that fileName. Works in Bourne, Korn, Bash and Z shells.

diff <(ssh server01 'cd config; find . -type f -exec md5sum {} \;| sort -k 2') <(ssh server02 'cd config;find . -type f -exec md5sum {} \;| sort -k 2')
2009-09-11 15:24:59
User: arcege
Functions: diff find md5sum sort ssh
13

This can be much faster than downloading one or both trees to a common servers and comparing the files there. After, only those files could be copied down for deeper comparison if needed.

echo src::${PATH} | awk 'BEGIN{pwd=ENVIRON["PWD"];RS=":";FS="\n"}!$1{$1=pwd}$1!~/^\//{$1=pwd"/"$1}{print $1}'
2009-09-09 04:03:46
User: arcege
Functions: awk echo
Tags: awk echo PATH
-2

Removes trailing newline; colon becomes record separator and newline becomes field separator, only the first field is ever printed. Replaces empty entries with $PWD. Also prepend relative directories (like ".") with the current directory ($PWD). Can change PWD with env(1) to get tricky in (non-Bourne) scripts.

curl -Is slashdot.org | sed -ne '/^X-[FBL]/s/^X-//p'
awk 'BEGIN {a=1;b=1;for(i=0;i<'${NUM}';i++){print a;c=a+b;a=b;b=c}}'
2009-09-06 03:05:55
User: arcege
Functions: awk
Tags: awk
0

Does not require input to function or complete. Number of iterations controlled by shell variable $NUM.

find . -name .svn -prune -o -print
2009-09-04 17:41:33
User: arcege
Functions: find
Tags: svn find
5

Put the positive clauses after the '-o' option.

svn log fileName | sed -ne "/^r\([0-9][0-9]*\).*/{;s//\1/;s/.*/svn cat fileName@& > fileName.r&/p;}" | sh -s
2009-09-04 17:23:45
User: arcege
Functions: sed sh
Tags: svn sed shell
2

Manages everything through one sed script instead of pipes of greps and awks. Quoting of shell variables is generally easier within a sed script.

find . -type f -name '*.c' -exec wc -l {} \; | awk '{sum+=$1} END {print sum}'
2009-09-04 15:51:30
User: arcege
Functions: awk find wc
Tags: awk find wc
-1

Have wc work on each file then add up the total with awk; get a 43% speed increase on RHEL over using "-exec cat|wc -l" and a 67% increase on my Ubuntu laptop (this is with 10MB of data in 767 files).

find . -type f -exec grep -qi 'foo' {} \; -print0 | xargs -0 vim
2009-09-03 17:55:26
User: arcege
Functions: find grep xargs
Tags: vim find grep
-1

Make sure that find does not touch anything other than regular files, and handles non-standard characters in filenames while passing to xargs.

bash -x test.sh 2>&1 | tee out.test
2009-09-03 17:10:44
User: arcege
Functions: bash tee
3

Sends both stdout and stderr to the pipe which captures the data in the file 'out.test' and sends to stdout of tee (likely /dev/tty unless redirected). Works on Bourne, Korn and Bash shells.