Berkeley CSUA MOTD:Entry 23668
Berkeley CSUA MOTD
 
WIKI | FAQ | Tech FAQ
http://csua.com/feed/
2025/04/07 [General] UID:1000 Activity:popular
4/7     

2002/1/25-26 [Computer/SW/Unix, Computer/SW/Languages/Perl] UID:23668 Activity:high
1/24    Is there a way to do the substr function in a shell script?
        I want do command | foo 4 10 to get the 4th to 10th character
        of output.  Thanks!
        \_ printf(1) might work
        \_ cut -c 4-10 if you want 4th through 10th of every line; otherwise
           you'll probably need some sed/perl hack since most UNIX utils
           treat lines as separate records. -alexf
        \_ Try awk '{print $x}' | cut -c 4-10  where x = your item in the line.
           If you need to do something with the rest of the line you can start
           playing with 'tee' and shit like that but perl is probably a better
           long term choice.
        \_ awk has a substr function.
           # substr($2,9,7) picks out characters 9 thru 15 of column 2
           {print "imarith", substr($2,9,7) " - " $3, "out."substr($2,13,3)}
           --dim
ERROR, url_link recursive (eces.Colorado.EDU/secure/mindterm2) 2025/04/07 [General] UID:1000 Activity:popular
4/7     

You may also be interested in these entries...
2012/8/29-11/7 [Computer/SW/Security] UID:54467 Activity:nil
8/29    There was once a CSUA web page which runs an SSH client for logging
        on to soda.  Does that page still exist?  Can someone remind me of the
        URL please?  Thx.
        \_ what do you mean? instruction on how to ssh into soda?
           \_ No I think he means the ssh applet, which, iirc, was an applet
              that implemented an ssh v1 client.  I think this page went away
	...
2012/9/20-11/7 [Computer/SW/Unix, Finance/Investment] UID:54482 Activity:nil
9/20    How do I change my shell? chsh says "Cannot change ID to root."
        \_ /usr/bin/chsh does not have the SUID permission set. Without
           being set, it does not successfully change a user's shell.
           Typical newbie sys admin (on soda)
           \_ Actually, it does: -rwsr-xr-x 1 root root 37552 Feb 15  2011 /usr/bin/chsh
	...
2012/9/24-11/7 [Computer/SW/Languages, Computer/SW/Unix] UID:54484 Activity:nil
9/24    How come changing my shell using ldapmodify (chsh doesn't work) doesn't
        work either? ldapsearch and getent show the new shell but I still get
        the old shell on login.
        \_ Scratch that, it magically took my new shell now. WTF?
           \_ probably nscd(8)
	...
2012/3/29-6/4 [Computer/HW/Memory, Computer/HW/CPU, Computer/HW/Drives] UID:54351 Activity:nil
3/29    A friend wants a PC (no mac). She doesn't want Dell. Is there a
        good place that can custom build for you (SSD, large RAM, cheap video
        card--no game)?
        \_ As a side note: back in my Cal days more than two decades ago when
           having a 387SX made me the only person with floating-point hardware,
           most machines were custom built.
	...
2012/4/27-6/4 [Computer/SW/Languages/Misc, Computer/SW/Unix] UID:54372 Activity:nil
4/27    I wrote a little shell script to collect iostat data:
        #!/bin/bash
        DATE=`date +%m%d`
        DATADIR=/var/tmp/user
        OUTPUTFILE=$DATADIR/$DATE.out
        while true
	...
2012/1/27-3/26 [Computer/SW/Unix] UID:54299 Activity:nil
1/27    Interesting list of useful unix tools. Shout out to
        cowsay even!
        http://www.stumbleupon.com/su/3428AB/kkovacs.eu/cool-but-obscure-unix-tools
        \_ This is nice.  Thanks.
	...
2011/10/26-12/6 [Computer/SW/Unix] UID:54202 Activity:nil
10/24  What's an easy way to see if say column 3 of a file matches a list of
       expressions in a file? Basically I want to combine "grep -f <file>"
       to store the patterns and awk's $3 ~ /(AAA|BBB|CCC)/ ... I realize
       I can do this with "egrep -f " and use regexp instead of strings, but
       was wondering if there was some magic way to do this.
       \_ UNIX has no magic. Make a shell script to produce the ask or egrep
	...
2011/5/19-7/13 [Computer/SW/Languages/Misc] UID:54115 Activity:nil
5/19    If script A runs, and calls script B ..... is it possible for me to exit\
        script A based on results of script B and not continue?
        \_ assume any shell
        \_ Yes.
           \_ without passing the result to some stupid temp file?
              \_ It sounds like you want "scriptb || exit", which will run
	...